Webster's Revised Unabridged Dictionary · 1913

Solo

Solo (sō"lo) , noun

[Italian, from Latin solus alone. See Sole, a.]

(Music) A tune, air, strain, or a whole piece, played by a single person on an instrument, or sung by a single voice.

Solo , adjective

(Music) Performing, or performed, alone; uncombined, except with subordinate parts, voices, or instruments; not concerted.