The Collaborative International Dictionary of English v.0.48:
Philatelist \Phi*lat"e*list\, n. One versed in philately; one who collects postage stamps, as a hobby or for investment; a stamp collector. [1913 Webster]WordNet (r) 3.0 (2006):
philatelist n 1: a collector and student of postage stamps [syn: philatelist, stamp collector]