TKG English Learner's Dictionary

because

becauseconjunction

American /bɪˈkɔz/ British /bɪˈkɒz/ also (American) /bɪˈkʌz/ also common also /kəz/ in relaxed speech; written cuz or 'cause in messages The stress is on the second syllable.
very commondefining vocabulary

Because introduces the reason for what is said.

  1. giving a reasonfor the reason that

    A because clause has a subject and a verb. It usually comes after the main clause, with no comma, but it can come first, with a comma after it: Because it was late, we left. It answers the question why? and can stand alone as an answer in speech: Why? Because I said so.

    Collocations

    phrase just because, only because, partly because, mainly because, simply because, not because ... but because

    Synonyms since (since is a little more formal and often gives a reason the listener already knows); as (as gives a reason more lightly and is common in writing)

    Compare because of (because of goes before a noun or pronoun, not a clause: because of the rain); so (so introduces the result; because introduces the reason: It rained, so we stayed in. We stayed in because it rained.); since; as

  2. just becauseused with just to say that one fact does not prove another

    The whole just because clause is the subject, and the sentence says that one thing does not follow from the other. It is common in speech and informal writing.

    informal

Word family

  • because of

Usage

The reason is because is common, but some careful writers prefer the reason is that, or simply because on its own: I left because I was bored.

Common mistakes

because of he was tired because he was tired
Because introduces a clause with a subject and a verb; because of goes before a noun: because of his tiredness.
Because it rained, so we stayed home. Because it rained, we stayed home.
Because and so are not used together when they mark the same reason; use one or the other.
I went to bed early. Because I was tired. I went to bed early because I was tired.
In careful writing, a because clause is joined to the sentence it explains; on its own, as in a spoken answer to why, it is informal.

See also because (the newer use directly before a noun (because movies), analyzed as a preposition, not a conjunction)

For translators

Meaning across languages Many languages have separate words for a reason the listener already knows and for a new one. English uses because for both, and keeps since and as mainly for the known reason in more formal style.
Grammar trap Because introduces a full clause with a subject and a verb and is not paired with so or therefore for the same reason, as it is in some languages. Before a noun phrase use because of: because of the rain.
Pronunciation trap Stress on the second syllable: bih-KUZ. In relaxed speech it shrinks to kuz, written cuz or 'cause in messages; learners should recognize this but write because.