From WordNet (r) 3.0 (2006) [wn]:
comedian
n 1: a professional performer who tells jokes and performs
comical acts [syn: comedian, comic]
2: an actor in a comedy
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Comedian \Co*me"di*an\, n. [Cf. F. com['e]dien.]
1. An actor or player in comedy. "The famous comedian,
Roscius." --Middleton.
[1913 Webster]
2. A writer of comedy. --Milton.
[1913 Webster]