Origin of than
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.
conjunction, preposition (coordinating)
Word Origin for than
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).
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.