than

[th an, th en; unstressed thuh n, uh n]
conjunction
  1. (used, as after comparative adjectives and adverbs, to introduce the second member of an unequal comparison): She's taller than I am.
  2. (used after some adverbs and adjectives expressing choice or diversity, such as other, otherwise, else, anywhere, or different, to introduce an alternative or denote a difference in kind, place, style, identity, etc.): I had no choice other than that. You won't find such freedom anywhere else than in this country.
  3. (used to introduce the rejected choice in expressions of preference): I'd rather walk than drive there.
  4. except; other than: We had no choice than to return home.
  5. when: We had barely arrived than we had to leave again.
preposition
  1. in relation to; by comparison with (usually followed by a pronoun in the objective case): He is a person than whom I can imagine no one more courteous.

Origin of than

before 900; Middle English, Old English than(ne) than, then, when, variant (in special senses) of thonne then; cognate with German dann then, denn than, Dutch dan then, than
Can be confusedthan then

Usage note

Whether than is to be followed by the objective or subjective case of a pronoun is much discussed in usage guides. When, as a conjunction, than introduces a subordinate clause, the case of any pronouns following than is determined by their function in that clause: He is younger than I am. I like her better than I like him. When than is followed only by a pronoun or pronouns, with no verb expressed, the usual advice for determining the case is to form a clause mentally after than to see whether the pronoun would be a subject or an object. Thus, the sentences He was more upset than I and She gave him more sympathy than I are to be understood, respectively, as He was more upset than I was and She gave him more sympathy than I gave him. In the second sentence, the use of the objective case after than ( She gave him more sympathy than me ) would produce a different meaning ( She gave him more sympathy than she gave me ). This method of determining the case of pronouns after than is generally employed in formal speech and writing.
Than occurs as a preposition in the old and well-established construction than whom : a musician than whom none is more expressive. In informal, especially uneducated, speech and writing, than is usually treated as a preposition and followed by the objective case of the pronoun: He is younger than me. She plays better poker than him, but you play even better than her. See also but1, different, me.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for than

than

conjunction, preposition (coordinating)
  1. used to introduce the second element of a comparison, the first element of which expresses differenceshorter than you; couldn't do otherwise than love him; he swims faster than I run
  2. used after adverbs such as rather or sooner to introduce a rejected alternative in an expression of preferencerather than be imprisoned, I shall die
  3. other than besides; in addition to

Word Origin for than

Old English thanne; related to Old Saxon, Old High German thanna; see then

usage

In formal English, than is usually regarded as a conjunction governing an unexpressed verb: he does it far better than I (do). The case of any pronoun therefore depends on whether it is the subject or object of the unexpressed verb: she likes him more than I (like him); she likes him more than (she likes) me . However in ordinary speech and writing than is usually treated as a preposition and is followed by the object form of a pronoun: my brother is younger than me
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for than
conj.

Old English þan, conjunctive particle used after a comparative adjective or adverb, from þanne, þænne, þonne "then" (see then). Developed from the adverb then, and not distinguished from it in spelling until c.1700.

The earliest use is in West Germanic comparative forms, i.e. bigger than (cf. Dutch dan, German denn), which suggests a semantic development from the demonstrative sense of then: A is bigger than B, evolving from A is bigger, then ("after that") B. Or the word may trace to Old English þonne "when, when as," such as "When as" B is big, A is more (so).

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with than

than

see actions speak louder than words; bark is worse than one's bite; better late than never; better safe than sorry; better than; bite off more than one can chew; blood is thicker than water; easier said than done; eyes are bigger than one's stomach; in (less than) no time; irons in the fire, more than one; less than; more dead than alive; more fun than a barrel of monkeys; more in sorrow than in anger; more often than not; more sinned against than sinning; more than meets the eye; more than one bargained for; more than one can shake a stick at; more than one way to skin a cat; none other than; no sooner said than done; other than; quicker than you can say Jack Robinson; wear another (more than one) hat.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.