solo n.

1690s, "piece of music intended for one voice or instrument," also a performance of such, from Italian solo, literally "alone," from Latin solus "alone" (see sole (adj.)). In reference to dance from 1794. As an adjective in English from 1712, originally in the non-musical sense of "alone, unassisted." Of musicians or instruments, "play a solo part," 1862. in reference to aircraft flights from 1909. The verb is attested by 1858 in music, 1886 in a non-musical sense. Related: Soloed; soloing.