Standard Lemma guide

patent

adj · noun · verb · 29 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

Each Play button uses your device's default local English voice, or a natural local fallback. The selected voice name appears after playback. This is synthesized speech, not a source recording.

  • Received-Pronunciation: /ˈpeɪtənt/
  • Received-Pronunciation: /ˈpætənt/
  • Received-Pronunciation: Recorded audio is listed in the source snapshot.
  • Canada, General-American: pătʹənt
  • Canada, General-American: pātʹənt
  • Canada, General-American: /ˈpætənt/
  • Canada, General-American: [ˈphæ̝ʔn̩t̚]
  • Canada, General-American: /ˈpeɪtənt/
  • Canada, General-American: [ˈphe̞ɪʔn̩t̚]
  • New-Jersey: Recorded audio is listed in the source snapshot.
  • Australian: /ˈpæɪtənt/
  • Australian: /ˈpætənt/
  • rhymes with -eɪtənt
  • rhymes with -ætənt
  • CMU ARPABET: P AE1 T AH0 N T Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.

1

adj

Meaning 1

Conspicuous; open; unconcealed.

Definition source: English Wiktionary via Wiktextract

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: overt

Antonyms: none provided

2

adj

Meaning 2

Conspicuous; open; unconcealed.

Of flour: fine, and consisting mostly of the inner part of the endosperm of the grain from which it is milled.

Definition source: English Wiktionary via Wiktextract

Topics: baking, cooking, food, lifestyle

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: overt

Antonyms: none provided

3

adj

Meaning 3

Conspicuous; open; unconcealed.

Open, unobstructed; specifically, especially of the ductus arteriosus or foramen ovale in the heart, having not closed as would have happened in normal development.

Definition source: English Wiktionary via Wiktextract

Topics: medicine, sciences

Examples

  • She has a patent ductus arteriosus that will require surgery to close.

Meaning relationships

Synonyms: overt

Antonyms: none provided

4

adj

Meaning 4

Conspicuous; open; unconcealed.

Of an infection: in the phase when the organism causing it can be detected by clinical tests.

Definition source: English Wiktionary via Wiktextract

Topics: biology, medicine, natural-sciences, pathology, sciences, veterinary, zoology

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: overt

Antonyms: none provided

5

adj

Meaning 5

Explicit and obvious.

Definition source: English Wiktionary via Wiktextract

Examples

  • Those claims are patent nonsense.

Meaning relationships

Synonyms: express, monosemous, unambiguous, clear, direct, explicit, monosemic, patent, plain, specific, unequivocal, univocal, apparent, arrant, undoubted, glaring, bait, blatant, clear as a bell, clear as day, clear cut, conspicuous, crystal clear, cut and dried, decided, elucidate, evident, eyely, intuitive, manifest, notable, noticeable, obvious, open-and-shut, ostensible, palpable, plain as a haystack, plain as a pikestaff, plain as day, plain as Dunstable highway, plain as porridge, plain as print, plain as Salisbury, plain as the nose on one's face, prima facie, res ipsa loquitur, splendent, straightforward, undissembled

Antonyms: none provided

6

adj

Meaning 6

Especially of a document conferring some privilege or right: open to public perusal or use.

Definition source: English Wiktionary via Wiktextract

Usage: archaic

Examples

  • letters patent

Meaning relationships

Synonyms: none provided

Antonyms: none provided

7

adj

Meaning 7

Appointed or conferred by letters patent.

Definition source: English Wiktionary via Wiktextract

Usage: archaic

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

8

adj

Meaning 8

Of a branch, leaf, etc.: outspread; also, spreading at right angles to the axis.

Definition source: English Wiktionary via Wiktextract

Topics: biology, botany, natural-sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

9

adj

Meaning 9

Protected by a legal patent.

Definition source: English Wiktionary via Wiktextract

Topics: law

Examples

  • a patent right patent medicines

Meaning relationships

Synonyms: patented

Antonyms: none provided

10

adj

Meaning 10

To which someone has, or seems to have, a claim or an exclusive claim; also, inventive or particularly suited for.

Definition source: English Wiktionary via Wiktextract

Usage: broadly, figuratively

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

11

noun

Meaning 11

An official document granting an appointment, privilege, or right, or some property or title; letters patent.

Definition source: English Wiktionary via Wiktextract

Usage: countable, uncountable

Topics: law

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

12

noun

Meaning 12

A grant of a monopoly over the manufacture, sale, and use of goods.

Definition source: English Wiktionary via Wiktextract

Usage: countable, specifically, uncountable

Qualifier: originally

Topics: law

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

13

noun

Meaning 13

A declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period.

Definition source: English Wiktionary via Wiktextract

Usage: countable, specifically, uncountable

Topics: law

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

14

noun

Meaning 14

A specific grant of ownership of a piece of real property; a land patent.

Definition source: English Wiktionary via Wiktextract

Usage: US, countable, historical, uncountable

Topics: law

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

15

noun

Meaning 15

A product in respect of which a patent (sense 1.2.2) has been obtained.

Definition source: English Wiktionary via Wiktextract

Usage: broadly, countable, uncountable

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

16

noun

Meaning 16

Ellipsis of patent leather (“a varnished, high-gloss leather typically used for accessories and shoes”).

Definition source: English Wiktionary via Wiktextract

Usage: abbreviation, alt-of, ellipsis, uncountable

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

17

noun

Meaning 17

A licence or (formal) permission to do something.

Definition source: English Wiktionary via Wiktextract

Usage: countable, figuratively, uncountable

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

18

noun

Meaning 18

A characteristic or quality that one possesses; in particular (hyperbolic) as if exclusively; a monopoly.

Definition source: English Wiktionary via Wiktextract

Usage: countable, figuratively, uncountable

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

19

noun

Meaning 19

The combination of seven bets on three selections, offering a return even if only one bet comes in.

Definition source: English Wiktionary via Wiktextract

Usage: countable, uncountable

Topics: gambling, games

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

20

verb

Meaning 20

To (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period.

Definition source: English Wiktionary via Wiktextract

Usage: transitive

Topics: law

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

21

verb

Meaning 21

To obtain (over a piece of real property) a specific grant of ownership.

Definition source: English Wiktionary via Wiktextract

Usage: US, historical, transitive

Topics: law

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

22

verb

Meaning 22

To be closely associated or identified with (something); to monopolize.

Definition source: English Wiktionary via Wiktextract

Usage: figuratively, transitive

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

23

adjective satellite

Meaning 23

clearly revealed to the mind or the senses or judgment

Definition source: Princeton WordNet 3.0

Examples

  • the effects of the drought are apparent to anyone who sees the parched fields
  • evident hostility
  • manifest disapproval
  • patent advantages
  • made his meaning plain
  • it is plain that he is no reactionary
  • in plain view

Meaning relationships

Synonyms: apparent, evident, manifest, plain, unmistakable

Antonyms: none provided

24

adjective satellite

Meaning 24

(of a bodily tube or passageway) open; affording free passage

Definition source: Princeton WordNet 3.0

Examples

  • patent ductus arteriosus

Meaning relationships

Synonyms: none provided

Antonyms: none provided

25

noun

Meaning 25

a document granting an inventor sole rights to an invention

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: patent of invention

Antonyms: none provided

Broader terms: document, written document, papers

26

noun

Meaning 26

an official document granting a right or privilege

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: letters patent

Antonyms: none provided

Broader terms: legal document, legal instrument, official document, instrument

27

verb

Meaning 27

make open to sight or notice

Definition source: Princeton WordNet 3.0

Examples

  • His behavior has patented an embarrassing fact about him

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: change, alter, modify

28

verb

Meaning 28

obtain a patent for

Definition source: Princeton WordNet 3.0

Examples

  • Should I patent this invention?

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: procure, secure

29

verb

Meaning 29

grant rights to; grant a patent for

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: register

History

Etymology

From Middle English patent, patente (“wide open; clear, unobstructed; unlimited; of a document: available for public inspection”) [and other forms], from Anglo-Norman and Middle French patent (modern French patent), and directly from their etymon Latin patēns (“open; accessible, passable; evident, manifest; exposed, vulnerable”), the present active participle of pateō (“to be open; to be accessible, attainable; to be exposed, vulnerable; of frontiers or land: to extent, increase”), from Proto-Indo-European *peth2- (“to spread out; to fly”).

The noun is derived from Middle English patent (“document granting an office, property, right, title, etc.; document granting permission, licence; papal indulgence, pardon”) [and other forms], which is either: * a clipping of lettre patent, lettres patente, lettres patentes [and other forms]; or * directly from Anglo-Norman and Middle French patente (modern French patent), a clipping of Anglo-Norman lettres patentes, Middle French lettres patentes, lettre patente, and Old French patentes lettres (“document granting an office, privilege, right, etc., or making a decree”) (compare Late Latin patēns, littera patēns, litterae patentēs). For the derivation of Anglo-Norman and Middle French patente (adjective) in lettre patente, see etymology 2 below. The verb is derived from the noun.

Across languages

Translations

98 source translations are retained for this English entry.

  • Bulgarian: явен (javen) — explicit and obvious — see also explicit, obvious
  • Bulgarian: очевиден (očeviden) — explicit and obvious — see also explicit, obvious
  • Catalan: patent — explicit and obvious — see also explicit, obvious
  • Finnish: suoranainen — explicit and obvious — see also explicit, obvious
  • Finnish: ilmeinen — explicit and obvious — see also explicit, obvious
  • Irish: paiteanta — explicit and obvious — see also explicit, obvious
  • Japanese: 明らかな (akirakana) — explicit and obvious — see also explicit, obvious
  • Occitan: patent — explicit and obvious — see also explicit, obvious
  • Occitan: clar — explicit and obvious — see also explicit, obvious
  • Occitan: evident — explicit and obvious — see also explicit, obvious
  • Persian: عیان ('ayân) — explicit and obvious — see also explicit, obvious
  • Polish: oczywisty — explicit and obvious — see also explicit, obvious
  • Portuguese: patente — explicit and obvious — see also explicit, obvious
  • Russian: очеви́дный (očevídnyj) — explicit and obvious — see also explicit, obvious
  • Russian: я́вный (jávnyj) — explicit and obvious — see also explicit, obvious
  • Spanish: patente — explicit and obvious — see also explicit, obvious
  • Finnish: avoin — (medicine) open, unobstructed
  • Italian: pervio — (medicine) open, unobstructed
  • Finnish: patentoitu — protected by a legal patent
  • Māori: mana waihanga — grant of a monopoly over the manufacture, sale, and use of goods
  • Arabic: بَرَاءَة اِخْتِرَاع — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Armenian: արտոնագիր (artonagir) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Bulgarian: патент (patent) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Burmese: မူပိုင် (mupuing) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Burmese: မူပိုင်ခွင့် (mupuinghkwang.) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Catalan: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Chinese Mandarin: 專利 /专利 (zhuānlì) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Czech: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Danish: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Dutch: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Dutch: octrooi — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Finnish: patentti — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • French: brevet — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Georgian: პატენტი (ṗaṭenṭi) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • German: Patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Greek: πατέντα (paténta) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Greek: ευρεσιτεχνία (evresitechnía) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Hindi: पेटेंट (peṭeṇṭ) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Hindi: पेटेण्ट (peṭeṇṭ) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Hindi: अनन्याधिकार (ananyādhikār) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Hindi: पेटेन्ट (peṭenṭ) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Hungarian: szabadalom — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Indonesian: paten — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Indonesian: oktroi — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Italian: brevetto — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Japanese: 特許 (tokkyo) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Japanese: 専売特許 (senbai tokkyo) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Kazakh: иеқұжат (ieqūjat) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Khmer: ប៉ាតង (paatɑɑng) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Korean: 특허 (teukheo) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Korean: 특허권 (teukheogwon) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Lao: ປະຕັງ — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Luxembourgish: Patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Luxembourgish: Brevet — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Māori: manatitonga — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Mongolian: патент (patent) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Mongolian: тусгай ашиг (tusgaj ašig) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Mongolian: ᠫᠠᠲ᠋ᠧᠨ᠍ᠲ (patēnt) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Mongolian: ᠲᠤᠰᠬᠠᠶ ᠠᠰᠢᠭ (tusqay asiɣ) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Occitan: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Polish: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Portuguese: patente — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Russian: пате́нт (patént) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Serbo-Croatian: па̀тент — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Serbo-Croatian: pàtent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Spanish: patente — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Swedish: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Tagalog: karapatang-tuklas — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Thai: สิทธิบัตร (sìt-tí-bàt) — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Turkish: buluş belgesi — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Turkish: patent — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Vietnamese: bằng độc quyền sáng chế — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Vietnamese: bằng sáng chế — declaration issued by a government agency that the inventor of a new invention has the sole privilege of making, selling, or using the claimed invention for a specified period
  • Finnish: maaoikeus — specific grant of ownership of a piece of property
  • Hindi: पेटेंट (peṭẽṭ) — specific grant of ownership of a piece of property
  • Japanese: 権利証 (kenri shō) — specific grant of ownership of a piece of property
  • Finnish: patentoitu tuote — product in respect of which a patent has been obtained
  • Finnish: patentti — characteristic or quality that one possesses; in particular as if exclusively — see also monopoly
  • Finnish: monopoli — characteristic or quality that one possesses; in particular as if exclusively — see also monopoly
  • Bulgarian: патентовам (patentovam) — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Catalan: patentar — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Dutch: patenteren — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Finnish: patentoida — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • French: breveter — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • French: faire breveter — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • German: patentieren — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • German: patentieren lassen — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Hindi: पेटेंट करना (peṭẽṭ karnā) — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Hungarian: szabadalmaztat — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Japanese: 特許取得 (tokkyo shutoku) — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Occitan: patentar — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Polish: patentować — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Polish: opatentować — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Portuguese: patentear — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Russian: брать пате́нт (bratʹ patént) — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Russian: патентова́ть (patentovátʹ) — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Spanish: patentar — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
  • Swedish: patentera — to (successfully) register (a new invention) with a government agency to obtain the sole privilege of its manufacture, sale, and use for a specified period
Real reading context

patent in complete knowledge articles