The Collaborative International Dictionary of English v.0.48:

Histrion \His"tri*on\, n. [L. histrio: cf. F. histrion.]
   A player. [R.] --Pope. Histrionic

WordNet (r) 3.0 (2006):

histrion
    n 1: a theatrical performer [syn: actor, histrion, player,
         thespian, role player]