A preposition links a noun or pronoun to the rest of a sentence, usually showing place, time, direction or relationship, such as in, on, or with. A conjunction connects words, phrases or clauses, such as and, but, or because. In "the keys are on the table," on is a preposition; in "although it was late, we stayed," although is a conjunction.
The core difference
A preposition relates a noun to the rest of the sentence, while a conjunction joins words, phrases or clauses together.
- preposition — a word like in, on, at, to, from, with or by that links a noun or pronoun to the rest of the sentence: in "the keys are on the table," "on" is a preposition.
- conjunction — a word that connects other words, phrases, or clauses, such as "and," "but," or "because": "although" is a conjunction that introduces a contrast.
How to tell them apart
A preposition sits before a noun or pronoun and ties it to the rest of the sentence, usually pinning down place, time or direction — think of it as answering "where," "when" or "how" something relates to something else. A conjunction, on the other hand, is a connector: it links two words, two phrases, or two whole clauses, joining ideas rather than positioning them.
Learners often struggle with English prepositions in particular because their use is idiomatic — there's rarely a logical reason why it's "interested in" but "keen on," so these are usually learned one phrase at a time rather than worked out from a rule.
