WordNet (r) 3.0 (2006):

ukulele
    n 1: a small guitar having four strings [syn: uke, ukulele]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "ukulele":
   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, sitar,
   steel guitar, tamboura, theorbo, troubadour fiddle, uke