BASS, the lowest in the four parts of music: of uncertain etymology; whether from the Greek word basis, "a foundation;" or from the Italian adjective basso, signifying "low." Of all the parts it is the most important, and it is upon this that the chords proper
to constitute a particular harmony are determined. Hence the maxim among musicians, that when the bass is properly formed, the harmony can scarcely be bad.
Basses are of different kinds. Of which in their order.
Thorough-BASS is the harmony made by the bass-viol, or theorbos, continuing to play both while the voices sing and the other instruments perform their parts, and also filling up the intervals when any of the other parts stop. It is played by figures marked over the notes, on the organ, spinet, harpsichord, &c. and frequently simply and without figures on the bass-viol and bassoon.
Counter-BASS is a second or double bass, where there are several in the same concert.