WordNet (r) 3.0 (2006):

sitar
    n 1: a stringed instrument of India; has a long neck and movable
         frets; has 6 or 7 metal strings for playing and usually 13
         resonating strings

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "sitar":
   Dobro guitar, F-hole guitar, Spanish guitar, archlute, balalaika,
   banjo, banjo-uke, banjo-ukulele, banjo-zither, banjorine, banjuke,
   bass guitar, centerhole guitar, concert guitar, electric guitar,
   guitar, lute, mando-bass, mando-cello, mandola, mandolin,
   mandolute, mandore, oud, pandora, pandura, samisen, steel guitar,
   tamboura, theorbo, troubadour fiddle, uke, ukulele