Source : Webster's Revised Unabridged Dictionary (1913)

Obligato \Ob"li*ga"to\, a. [It.]
   See {Obbligato}.

Source : WordNet®

obligato
     n 1: a persistent but subordinate motif [syn: {obbligato}]
     2: a part of the score that must be performed without change or
        omission [syn: {obbligato}]
     [also: {obligati} (pl)]