The Collaborative International Dictionary of English v.0.48:

Betelguese \Bet"el*guese\ (b[e^]t"[e^]l*j[=e]z), n. [F.
   B['e]telgeuse, of Arabic origin.] (Astron.)
   A bright star of the first magnitude, near one shoulder of
   Orion. [Written also Betelgeux and Betelgeuse.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Betelgeuse
    n 1: the second brightest star in Orion [syn: Betelgeuse,
         Alpha Orionis]