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# cos

conjunction (informal spoken form of "because"); also abbreviation cos (maths: cosine)

«cos» in the English dictionary: everyday — its meanings, how the lessons use it, and examples, each with its tree on Mova.

## Everyday

1. (slang, informal, UK and elsewhere) A short spoken form of "because", also written 'cause or coz. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#m1)
2. (maths) Short for "cosine", a function used with angles in triangles (older pupils). [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#m2)

### In the lessons

Children hear "cos" in casual talk all the time: "I'm late cos the bus broke down". In real-speech lessons it signals a reason, just like "because". In secondary maths, cos is written next to an angle: cos 60°. Not used in formal writing.

### Examples

- I didn't go out cos it was raining. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#x1)
- "Why are you laughing?" "Cos your face is funny!" [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#x2)
- We stayed in cos Mum said so. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#x3)
- He's tired cos he stayed up late. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#x4)
- I like her cos she's kind. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#x5)
- On a calculator, press cos to find the cosine of an angle. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/#x6)

### Note

"Cos" is not a proper word for school writing; write "because". Pronounced "koz" when it means because. The maths "cos" is short for cosine and is said "koz" too. In a word problem "cos" introduces a reason; it does not change the numbers.

## On Mova

- [Trees and pragmatics of «cos» in the school dictionary](https://mova.elamur.ai/free/en/corpora/dictionaries/school/C/cos/): every meaning and example parsed by Mova, with its dependency tree and frames.
- [«cos» in the school dictionary](https://mova.elamur.ai/free/en/dictionaries/school/w/cos.html) on Mova free.