What is the operatic term for dramatic dialogue set to music?

Opera, a staged drama set to music in its entirely, made up of vocal pieces with instrumental accompaniment and usually with orchestral overtures and interludes. In some operas the music is continuous thorough out an act; in others its broken up into discrete pieces, or "numbers," separated or by recitative (dramatic type singing that approaches speech) or spoken dialogue.  

Explanation:

The term should be Parlando.

Explanation:

PARLANDO (pahr-LAHN-doh): A style of singing like ordinary speech or dialogue. It can occur in the middle of an aria. PATTER SONG: A song or aria in which the character sings as many words as possible in a short amount of time. PIANO-VOCAL SCORE: Usually a reduction of an opera's orchestral score.