cosine
/ˈkoʊ.saɪn/noun
cosine is spelled C-O-S-I-N-E: 6 letters and 2 syllables. It appears about once in every 3 million words in written English, the 52,337th most frequent word form (wordfreq, 2021 data). As a noun, cosine means “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” (English Wiktionary, September 2026). The plural of cosine is cosines.
How many letters and syllables are in cosine?
| Letters | 6: C-O-S-I-N-E |
|---|---|
| Syllables | 2 (from its pronunciation) |
| In writing | about once in every 3 million words; the 52,337th most frequent word form |
| Wrong spellings searched | none measured in search |
| Sounds like | |
| Rhymes with |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media); rhymes and same-letter words are computed by PlainSpell from its own word list.
How common is cosine?
Cosine appears about once in every 3 million words in written English, the 52,337th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce cosine?
- UK /ˈkəʊ.saɪn/
- US /ˈkoʊ.saɪn/
- Australia /ˈkəʉ.sɑɪn/
Cosine has 2 syllables (counted from the pronunciation).
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: LL-Q1860_(eng)-Vininn126-cosine.wav, Wikimedia Commons (author and licence on each file's page).
Words people confuse with cosine
Sounds like: cosign (Wiktionary's homophone list; some hold only in some accents).
Sources: English Wiktionary (homophones, alternative spellings).
What rhymes with cosine?
One word on PlainSpell end in the same sounds as cosine from its last stressed vowel (/oʊsaɪn/):
Computed by PlainSpell from the pronunciations in the English Wiktionary (dump of September 2, 2026): a rhyme shares every sound from the last stressed vowel to the end; ordered by written frequency (wordfreq 3.1).
Forms of cosine
- cosines plural
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
What does cosine mean?
The meanings the English Wiktionary records, quoted as written there (source below).
noun
- 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
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Cosine in Spanish, French, German and Portuguese
In the sense trigonometric function:
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does cosine come from?
From co- + sine, short for complementi sinus in Latin, meaning “sine of the complement”. Doublet of cosinus.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).