The Collaborative International Dictionary of English v.0.48:

geisha \gei"sha\ (g[=a]"sh[.a]), n.; pl. geisha
   (g[=a]"sh[.a]), Geishas (g[=a]"sh[.a]z). [Jap., art
   person.]
   A Japanese singing and dancing girl, trained to provide
   entertainment and company for a man or group of men.
   [Webster 1913 Suppl. +PJC]

WordNet (r) 3.0 (2006):

geisha
    n 1: a Japanese woman trained to entertain men with conversation
         and singing and dancing [syn: geisha, geisha girl]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "geisha":
   artist, artiste, ballerina, ballet dancer, ballet girl,
   ballroom dancer, belly dancer, burlesque queen, choral dancer,
   chorine, chorus boy, chorus girl, clog dancer, conjurer, coryphee,
   dancer, dancing girl, danseur noble, danseuse, ecdysiast,
   entertainer, exotic dancer, female impersonator, figurant,
   figurante, geisha girl, guisard, guiser, heel-and-toe dancer,
   hoofer, hula girl, impersonator, magician, mountebank, mummer,
   musician, nautch girl, peeler, performer, prestidigitator,
   public entertainer, show girl, singer, square-dancer, stripper,
   stripteaser, stripteuse, terpsichorean, vaudevillian,
   vaudevillist