Coz is a very informal way of writing because. It belongs in texts, chat, and the kind of writing that tries to sound like speech.

Coz isCoz 是 a very informal way of writing一種非常口語的寫法，用來寫 because因為。 It belongs in texts, chat它會出現在簡訊、聊天，and the kind of writing that tries to sound like speech以及那種想寫得像口語的文章裡。

You will also see 'cause and cuz doing the same job; none of these is for a school essay or a formal letter, where because is the word that looks as if you meant it.

You will also see你也會看到 'cause and cuz'cause 和 cuz doing the same job做著一樣的工作；none of these is for a school essay or a formal letter這些字都不適合用在學校作文或正式信件裡，where because is the word that looks as if you meant it在那些場合，because 才是看起來像你認真在寫的那個字。

People have said the short form out loud for a long time; coz is just one of the spellings that got written down.

People have said the short form out loud for a long time人們口語上講這個簡短形式已經很久了；coz is just one of the spellings that got written downcoz 只是被寫下來的其中一種拼法。

Though actually, if you open an old play, coz can mean cousin — a friendly short form, like “my dear coz.” That is a different use of the same letters, and it is not how people mean it in a text today.

Though actually不過其實，if you open an old play如果你打開一齣老劇本，coz can mean cousincoz 可能是 cousin（表親）的意思——a friendly short form一種親暱的簡稱，like “my dear coz.”像「my dear coz（我親愛的表親）」這樣。That is a different use of the same letters這是同樣幾個字母的不同用法，and it is not how people mean it in a text today跟今天大家在簡訊裡的意思不一樣。