1 introducing the second element in a comparison (you are older than he is; you are older than he).
Usage:
It is also possible to say you are older than him, with than treated as a preposition, esp. in less formal contexts.
2 introducing the second element in a statement of difference (anyone other than me).
Etymology: OE thanne etc., orig. the same word as THEN
Useful english dictionary. 2012.