# cos

/ˈkɔs/ (US)

Source: https://englishreference.com/word/cos
Updated: 2026-06-19

## Senses

### 1. because

conjunction · CEFR B1 · Informal · British English

a short way to write or say 'because' in casual conversation.

For teachers: an informal clipping of 'because', used primarily in spoken English or casual digital communication.

- I didn't go to the party cos I was feeling really tired.
- He decided to skip the lecture 'cos he'd already covered the material during his summer internship.

Usage: Often written with an apostrophe as 'cos to show letters are missing.

### 2. lettuce

noun · CEFR B2 · British English

a type of lettuce with long, crisp leaves, often used in Caesar salads.

For teachers: a variety of lettuce (Lactuca sativa var. longifolia) characterized by long, narrow, crisp leaves and a firm rib.

- We need to buy some cos lettuce for the salad tonight.
- The chef prefers using cos for its superior crunch and ability to hold heavy dressings without wilting.

Usage: Commonly referred to as 'romaine' in American English.

## Examples

- I'm staying home 'cos I'm tired.
- We didn't go to the beach 'cos the weather forecast predicted heavy rain all afternoon.
- The director chose to film in black and white 'cos he felt it captured the bleak atmosphere of the novel more effectively than color ever could.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.