Noun
(music) An early Baroque genre or style of music in which groups of instruments or voices share a melody, usually in alternation, and almost always over a basso continuo.
A piece of music in this style.
Source: en.wiktionary.orgMost of Allegri's published music, especially the instrumental music, is in the progressive early Baroque concertato style. Source: Internet
The term "a cappella" was originally intended to differentiate between Renaissance polyphony and Baroque concertato style. Source: Internet