conjunction

1. introducing the second element in a comparison, following an adjective or adverb in the comparative degree: if the first element is a subject, object, predicate nominative, etc., the second element is construed in the same way: [he is taller than I; she arrived earlier than the others; Mom liked you better than me]: sometimes, informally, this use of than is construed as a preposition and the second element as its object [he is taller than me]
2. expressing exception, following an adjective or adverb none other than Sam
3. when: used esp. following an inverted construction introduced by scarcely, hardly, barely, etc. scarcely had I seen her than she spoke to me
4. indicating difference or distinction, as:: this mainly informal use of than with different and differently is objected to by some
   1. introducing an adverbial clause Paris was different than I'd thought it would be
   2. linking nouns or pronouns her story is different than his

Etymology: ME than, thene, thonne < OE thenne, thanne, thonne, orig., then: for IE base see that