Solo, a term used in musical compositions of several parts, whether vocal or instrumental, to indicate a voice or instrument that is to perform alone or in a more prominent manner, as soprano solo, violino solo. The plural, soli, is used when two or more voices or instrumental parts are to be performed together, such parts, of course, never being doubled.—A composition for a single instrument accompanied is also termed a solo.
Solo
Chambers's Encyclopaedia, Volume 9: Bound to Swansea, p. 563
Source scan(s): p. 0576