cos

Meanings

1. 1abbreviationmathematics

   Cosine; in mathematics, a function that relates the angle in a right triangle to the ratio of the adjacent side to the hypotenuse.

   Grammar: Used in mathematical writing and on calculators; usually written as 'cos' followed by an angle.

   Patterns

   • cos θ
   • cos x
   • cosine of an angle

   In a right triangle, cos θ equals the adjacent side divided by the hypotenuse.

   Press the cos button to find the cosine of 60 degrees.

   The equation uses sin and cos to describe the wave.

2. 2conjunctioninformalBritish

   Because; used in informal British speech and writing.

   Grammar: Informal spelling of 'because'; common in text messages and casual conversation.

   Patterns

   • cos I ...
   • cos it ...

   I'm not going, cos I'm tired.

   She left early cos she had a meeting.

   We can't come cos we're busy.

Common combinations

cos lettuce

She bought a head of cos lettuce for the salad.

cos I said so

You can't go out, cos I said so.

cos of

We were late cos of the traffic.

Synonyms and how they differ

because

The standard, formal spelling; 'cos' is only for casual contexts.

since

More formal and often suggests a reason already known.

as

Formal and can mean 'because', but is less direct.

Commonly confused: cos or cause?

Practice

Make it your own

Write a sentence using “cos”, then check it and compare it with the examples above.

Explore more words