For

For is a common English function word used mainly as a preposition and, in some uses, as a conjunction. It marks a range of relationships, including purpose, benefit, recipient, duration, exchange, and comparison.

As a preposition, for introduces purpose as in I bought this for you; it indicates duration (for two weeks), recipient or beneficiary (a gift for you), and reason (for that reason). It can express exchange (paid for the tickets) and support or advocacy (vote for). It also appears in fixed phrases such as for example, for instance, for now, and for good.

As a conjunction, for can mean because, especially in older or more formal English: We canceled the trip, for we were late. The use as a causal conjunction is less common in contemporary speech but remains acceptable in literary or ceremonial contexts.

In computing and logic, for appears in constructs such as for loops in programming and in formal notation as the phrase for all to denote universal quantification. In these contexts, it helps structure repetition and generalization, separate from its everyday role as a preposition.

Etymology and history: The word derives from Old English for and has cognates in other Germanic languages. It has existed in English since ancient times, adapting to a wide range of grammatical and idiomatic uses across centuries.