Standard Lemma guide

cosine

noun · 2 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

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  • UK: /ˈkəʊ.saɪn/
  • US: /ˈkoʊ.saɪn/
  • US: Recorded audio is listed in the source snapshot.
  • Australian: /ˈkəʉ.sɑɪn/
  • rhymes with -əʊsaɪn
  • rhymes with -oʊsaɪn
  • homophone: cosign

1

noun

Meaning 1

In a right triangle, the ratio of the length of the side adjacent to an acute angle to the length of the hypotenuse. Symbol: cos

Definition source: English Wiktionary via Wiktextract

Topics: mathematics, sciences, trigonometry

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

noun

Meaning 2

ratio of the adjacent side to the hypotenuse of a right-angled triangle

Definition source: Princeton WordNet 3.0

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: cos

Antonyms: none provided

Broader terms: trigonometric function, circular function

History

Etymology

Etymology tree Proto-Indo-European *ḱe? Proto-Indo-European *ḱóm Proto-Italic *kom Proto-Italic *kom- Latin con- Latin co-der. English co- Proto-Indo-European *sinos Proto-Italic *sinus Latin sinusbor. English sine English cosine From co- + sine, short for complementi sinus in Latin, meaning “sine of the complement”. Doublet of cosinus.

Across languages

Translations

53 source translations are retained for this English entry.

  • Arabic: جَيْب تَمَام (jayb tamām) — trigonometric function
  • Armenian: կոսինուս (kosinus) — trigonometric function
  • Azerbaijani: kosinus — trigonometric function
  • Basque: kosinu — trigonometric function
  • Bulgarian: ко́синус (kósinus) — trigonometric function
  • Burmese: ကိုဆိုင်း (kuihcuing:) — trigonometric function
  • Catalan: cosinus — trigonometric function
  • Cebuano: kalidpa — trigonometric function
  • Chinese Mandarin: 餘弦 /余弦 (yúxián) — trigonometric function
  • Czech: kosinus — trigonometric function
  • Dutch: cosinus — trigonometric function
  • Esperanto: kosinuso — trigonometric function
  • Finnish: kosini — trigonometric function
  • French: cosinus — trigonometric function
  • Georgian: კოსინუსი (ḳosinusi) — trigonometric function
  • German: Kosinus — trigonometric function
  • Greek: συνημίτονο (synimítono) — trigonometric function
  • Hebrew: קוסינוס (cosinus) — trigonometric function
  • Hungarian: koszinusz — trigonometric function
  • Icelandic: kósínus — trigonometric function
  • Irish: comhshíneas — trigonometric function
  • Italian: coseno — trigonometric function
  • Japanese: コサイン (kosain) — trigonometric function
  • Japanese: 余弦 (yogen) — trigonometric function
  • Khmer: កូស៊ីនុស (kousiinuh) — trigonometric function
  • Korean: 코사인 (kosain) — trigonometric function
  • Korean: 여현 (yeohyeon) — trigonometric function
  • Latvian: kosinuss — trigonometric function
  • Macedonian: косинус (kosinus) — trigonometric function
  • Malay: kosinus — trigonometric function
  • Manx: co-heenys — trigonometric function
  • Māori: whenu — trigonometric function
  • Norwegian Bokmål: cosinus — trigonometric function
  • Norwegian Nynorsk: cosinus — trigonometric function
  • Polish: cosinus — trigonometric function
  • Polish: kosinus — trigonometric function
  • Portuguese: co-seno — trigonometric function
  • Portuguese: cosseno — trigonometric function
  • Romanian: cosinus — trigonometric function
  • Russian: ко́синус (kósinus) — trigonometric function
  • Serbo-Croatian: ко̀синус — trigonometric function
  • Serbo-Croatian: kòsinus — trigonometric function
  • Sicilian: cusinu — trigonometric function
  • Slovak: kosínus — trigonometric function
  • Slovene: kòsínus — trigonometric function
  • Spanish: coseno — trigonometric function
  • Swedish: cosinus — trigonometric function
  • Tagalog: kasinway — trigonometric function
  • Tamil: துணைசெவ்வளை (tuṇaicevvaḷai) — trigonometric function
  • Thai: โคไซน์ (koo-saai) — trigonometric function
  • Turkish: kosinüs — trigonometric function
  • Ukrainian: ко́синус (kósynus) — trigonometric function
  • Vietnamese: côsin — trigonometric function