because

because — conjunction

1. joins two parts of a sentence to show that the second part tells you why the fir

1.conjunctionA1
Definition

joins two parts of a sentence to show that the second part tells you why the first part happens or is true.

Example

Mia stayed home from school because she had a sore throat.

main clause + because + clause stating the cause

We took the train because the roads were closed by heavy snow.

Common collocations
  • just because
  • only because
  • mainly because
  • partly because
  • simply because
Synonyms
  • since

    more formal; usually when the reason is already known to the listener

  • as

    more formal and slightly weaker; common in writing, less in speech

  • for

    literary or formal; introduces a reason added as an afterthought

Grammar Patterns

main clause + because + clause

Because + clause, main clause

Usage Note

Distinguish from sense preposition/1: the conjunction is followed by a full clause with its own subject and verb (because + S + V), while the preposition pattern uses 'because of' + noun phrase. In writing, avoid starting a stand-alone sentence with 'Because' followed by only a fragment.

Common Mistakes

Because the bus was late.' (sentence fragment)
Because the bus was late, I missed my class.
'because' must connect two clauses, not stand alone.
I was tired because of I worked late.
I was tired because I worked late.
use 'because' before a clause, 'because of' before a noun phrase.

because — preposition

Word family

Synonym discussion

Sense: conjunction/1

All four introduce a reason, but they differ in tone, weight, and position. 'Because' is the everyday default and gives the strongest, most direct cause-and-effect link; the reason is usually new information for the listener. 'Since' and 'as' both signal that the reason is already known or obvious, so the focus is really on the main clause; 'since' is slightly more common, while 'as' feels a touch more written. 'For' is literary or formal and adds the reason almost as an afterthought, usually after a comma. Compare: 'I went home because I was tired' (plain explanation), 'Since you're here, let's start' (reason already shared), 'He smiled, for he knew the answer' (formal, reflective).

because ↗sinceas ↗for ↗

Common collocations

Adverbs

  • just because
  • only because
  • mainly because
  • partly because
  • simply because
  • precisely because

Phrases

  • because of
  • if only because
  • all the more because
  • not because... but because

Etymology

Old FrenchMiddle EnglishEnglish

Built in Middle English from the phrase 'by cause', a translation of Old French 'par cause' meaning 'by reason of'. Writers first used it with a following 'that' (by cause that = for the reason that), and over time the two words fused into a single conjunction and the 'that' dropped away. The bare prepositional use before a noun or adjective ('because homework') is a much later, internet-era development from the early 2010s.