[1] : The Collaborative International Dictionary of English v.0.48

terzetto \terzet"to\, n. it., dim. of terzo the third, l.
   tertius. see tierce. mus.
   a composition in three voice parts; a vocal rarely an
   instrumental trio.
   1913 webster tesla coil
see also:
tierce 

[2] : WordNet (r) 2.0

terzetto
     n : the cardinal number that is the sum of one and one and one
         syn: three, 3, iii, trio, threesome, tierce,
          leash, troika, triad, trine, trinity, ternary,
          ternion, triplet, tercet, trey, deuce-ace
     also: terzetti pl
see also:
three 3 iii trio threesome tierce 
leash troika triad trine trinity 
ternary ternion triplet tercet trey 
deuce-ace terzetti 

Terzetto >> T Words
Terzetto, definition of term: Terzetto
terzetto_pag1.html