Standard Lemma guide

dual

adj · noun · verb · 15 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: dyo͞oʹəl
  • Received-Pronunciation: jo͞oʹəl
  • /ˈd͡ʒuː.əl/ yod-coalescence
  • /ˈdjuː.əl/ non-yod-coalescence
  • UK: Recorded audio is listed in the source snapshot.
  • General-American: d(y)o͞o'əl
  • General-American: /ˈdul/
  • General-American: /ˈd(j)u.əl/
  • homophone: duel
  • homophone: jewel (yod-coalescence)
  • rhymes with -uːəl
  • CMU ARPABET: D UW1 AH0 L Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.
  • CMU ARPABET 2: D UW1 L Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.

1

adj

Meaning 1

Characterized by having two (usually equivalent) components.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Examples

  • a dual-motor vehicle

Meaning relationships

Synonyms: double, twin

Antonyms: none provided

2

adj

Meaning 2

Pertaining to two, pertaining to a pair of.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Examples

  • dual engine failure
  • dual citizenship

Meaning relationships

Synonyms: double, duplicate, dual, duplex, duple, twissel, twofold, twosome

Antonyms: none provided

3

adj

Meaning 3

Pertaining to a grammatical number in certain languages that refers to two of something, such as a pair of shoes.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: grammar, human-sciences, linguistics, sciences

Examples

  • Modern Arabic displays a dual number, as did Homeric Greek.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

4

adj

Meaning 4

Exhibiting duality.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: mathematics, natural-sciences, physical-sciences, physics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

5

adj

Meaning 5

Being the space of all linear functionals of (some other space).

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: linear-algebra, mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

6

adj

Meaning 6

Being the dual of some other category; containing the same objects but with source and target reversed for all morphisms.

Definition source: English Wiktionary via Wiktextract

Usage: not-comparable

Topics: category-theory, computing, engineering, mathematics, natural-sciences, physical-sciences, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: opposite

Antonyms: none provided

7

noun

Meaning 7

Of an item that is one of a pair, the other item in the pair.

Definition source: English Wiktionary via Wiktextract

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

8

noun

Meaning 8

Of a regular polyhedron with V vertices and F faces, the regular polyhedron having F vertices and V faces.

Definition source: English Wiktionary via Wiktextract

Topics: geometry, mathematics, sciences

Examples

  • The octahedron is the dual of the cube. The icosahedron is the dual of the dodecahedron.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

9

noun

Meaning 9

The dual number.

Definition source: English Wiktionary via Wiktextract

Topics: grammar, human-sciences, linguistics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

10

noun

Meaning 10

Of a vector in an inner product space, the linear functional corresponding to taking the inner product with that vector. The set of all duals is a vector space called the dual space.

Definition source: English Wiktionary via Wiktextract

Topics: mathematics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

11

noun

Meaning 11

A head-to-head match or meet between two teams, such as two high schools or colleges.

Definition source: English Wiktionary via Wiktextract

Topics: government, hobbies, lifestyle, martial-arts, military, politics, sports, war, wrestling

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

12

verb

Meaning 12

To convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.

Definition source: English Wiktionary via Wiktextract

Usage: transitive

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

13

adjective satellite

Meaning 13

a grammatical number category referring to two items or units as opposed to one item (singular) or more than two items (plural)

Definition source: Princeton WordNet 3.0

Examples

  • ancient Greek had the dual form but it has merged with the plural form in modern Greek

Meaning relationships

Synonyms: none provided

Antonyms: none provided

14

adjective satellite

Meaning 14

consisting of or involving two parts or components usually in pairs

Definition source: Princeton WordNet 3.0

Examples

  • an egg with a double yolk
  • a double (binary) star
  • double doors
  • dual controls for pilot and copilot
  • duple (or double) time consists of two (or a multiple of two) beats to a measure

Meaning relationships

Synonyms: double, duple

Antonyms: none provided

15

adjective satellite

Meaning 15

having more than one decidedly dissimilar aspects or qualities- R.W.Emerson-Frederick Harrison

Definition source: Princeton WordNet 3.0

Examples

  • a double (or dual) role for an actor
  • the office of a clergyman is twofold; public preaching and private influence
  • every episode has its double and treble meaning

Meaning relationships

Synonyms: double, twofold, two-fold, treble, threefold, three-fold

Antonyms: none provided

History

Etymology

PIE word *dwóh1 Borrowed from Latin dualis (“two”), from duo (“two”) + adjective suffix -alis.

Across languages

Translations

126 source translations are retained for this English entry.

  • Bulgarian: от две части (ot dve časti) — having two components
  • Catalan: dual — having two components
  • Dutch: tweeledig — having two components
  • Esperanto: duparta — having two components
  • Esperanto: duala — having two components
  • Esperanto: duobla — having two components
  • Esperanto: binara — having two components
  • Finnish: kaksi- — having two components
  • Finnish: kaksois- — having two components
  • Finnish: duaalinen — having two components
  • Finnish: duaali- — having two components
  • French: double — having two components
  • French: duel — having two components
  • French: dual — having two components
  • Hungarian: kettős — having two components
  • Indonesian: dwi — having two components
  • Italian: duale — having two components
  • Italian: doppio — having two components
  • Latin: duālis — having two components
  • Manx: dooblit — having two components
  • Polish: dwoisty — having two components
  • Polish: podwójny — having two components
  • Portuguese: dual — having two components
  • Russian: двойно́й (dvojnój) — having two components
  • Russian: дво́йственный (dvójstvennyj) — having two components
  • Slovene: dvojen — having two components
  • Spanish: dual — having two components
  • Welsh: deuol — having two components
  • Arabic: مُثَنًّى (muṯannan) — double
  • Arabic: دَبَل (dabal) — double
  • Bulgarian: двоен (dvoen) — double
  • Catalan: doble — double
  • Dutch: dubbel- — double
  • Esperanto: duobla — double
  • Finnish: kaksi- — double
  • Finnish: kaksinkertainen — double
  • French: double — double
  • Indonesian: ganda — double
  • Manx: dooblit — double
  • Polish: podwójny — double
  • Portuguese: duplo — double
  • Russian: двойно́й (dvojnój) — double
  • Russian: двоя́кий (dvojákij) — double
  • Russian: сдво́енный (sdvójennyj) — double
  • Slovene: dvojen — double
  • Spanish: dual — double
  • Swedish: dubbel- — double
  • Swedish: två- — double
  • Turkish: çift — double
  • Welsh: deuol — double
  • Welsh: dwbl — double
  • Arabic: مُثَنًّى (muṯannan) — in grammar
  • Arabic: مُثَنَّى (muṯanna) — in grammar
  • Armenian: երկակի (erkaki) — in grammar
  • Bulgarian: двойствен (dvojstven) — in grammar
  • Chinese Cantonese: 雙數 /双数 (soeng1 sou3) — in grammar
  • Chinese: 雙數 /双数 (siang-sò͘) — in grammar
  • Chinese Mandarin: 雙數 /双数 (shuāngshù) — in grammar
  • Czech: duálový — in grammar
  • Dutch: dualis- — in grammar
  • Dutch: tweevouds- — in grammar
  • Finnish: kaksikko- — in grammar
  • Finnish: duaalinen — in grammar
  • Finnish: duaali- — in grammar
  • French: duel — in grammar
  • German: dual — in grammar
  • Ancient Greek: δυϊκός (duïkós) — in grammar
  • Hebrew: זוגי — in grammar
  • Hindi: द्विवचन (dvivcan) — in grammar
  • Hungarian: kettős — in grammar
  • Hungarian: duális — in grammar
  • Indonesian: dual — in grammar
  • Japanese: 双数 (sōsū) — in grammar
  • Navajo: naakigo — in grammar
  • Middle Persian: dw — in grammar
  • Polish: podwójna — in grammar
  • Portuguese: dual — in grammar
  • Russian: дво́йственный (dvójstvennyj) — in grammar
  • Russian: дуа́лис (duális) — in grammar
  • Slovene: dvojinski — in grammar
  • Spanish: dual — in grammar
  • Swedish: dual — in grammar
  • Tagalog: dalawahan — in grammar
  • Thai: ทวิพจน์ — in grammar
  • Turkish: ikil — in grammar
  • Turkish: tesniye — in grammar
  • Volapük: telnumik — in grammar
  • Arabic: مُثَنَّى (muṯannā) — grammatical number of a noun marking two of something
  • Armenian: երկակի (erkaki) — grammatical number of a noun marking two of something
  • Armenian: երկակի թիվ (erkaki tʻiv) — grammatical number of a noun marking two of something
  • Bulgarian: двойствено число (dvojstveno čislo) — grammatical number of a noun marking two of something
  • Czech: duál — grammatical number of a noun marking two of something
  • Czech: dvojné číslo — grammatical number of a noun marking two of something
  • Danish: dualis — grammatical number of a noun marking two of something
  • Dutch: dualis — grammatical number of a noun marking two of something
  • Dutch: tweevoud — grammatical number of a noun marking two of something
  • Faroese: tvítal — grammatical number of a noun marking two of something
  • Finnish: kaksikko — grammatical number of a noun marking two of something
  • Finnish: duaali — grammatical number of a noun marking two of something
  • French: duel — grammatical number of a noun marking two of something
  • German: Dual — grammatical number of a noun marking two of something
  • German: Zweizahl — grammatical number of a noun marking two of something
  • Greek: δυϊκός αριθμός (dyïkós arithmós) — grammatical number of a noun marking two of something
  • Ancient Greek: δυϊκόν (duïkón) — grammatical number of a noun marking two of something
  • Hungarian: kettős szám — grammatical number of a noun marking two of something
  • Hungarian: duális — grammatical number of a noun marking two of something
  • Irish: déach — grammatical number of a noun marking two of something
  • Japanese: 双数形 (sōsūkē) — grammatical number of a noun marking two of something
  • Latvian: divskaitlis — grammatical number of a noun marking two of something
  • Lithuanian: dviskaita — grammatical number of a noun marking two of something
  • Navajo: nizhdiltʼéhígo — grammatical number of a noun marking two of something
  • Norwegian Bokmål: dualis — grammatical number of a noun marking two of something
  • Norwegian Bokmål: totall — grammatical number of a noun marking two of something
  • Polish: liczba podwójna — grammatical number of a noun marking two of something
  • Portuguese: dual — grammatical number of a noun marking two of something
  • Russian: дво́йственное число́ (dvójstvennoje čisló) — grammatical number of a noun marking two of something
  • Samogitian: dvėskaita — grammatical number of a noun marking two of something
  • Serbo-Croatian: двојѝна — grammatical number of a noun marking two of something
  • Serbo-Croatian: dvojìna — grammatical number of a noun marking two of something
  • Slovene: dvojina — grammatical number of a noun marking two of something
  • Upper Sorbian: dwojota — grammatical number of a noun marking two of something
  • Upper Sorbian: dwójba — grammatical number of a noun marking two of something
  • Swedish: dualis — grammatical number of a noun marking two of something
  • Thai: ทวิพจน์ — grammatical number of a noun marking two of something
  • Ukrainian: двоїна́ (dvojiná) — grammatical number of a noun marking two of something
  • Volapük: telnum — grammatical number of a noun marking two of something