Sole

Webster's Practical Dictionary- A Practical Dictionary of the Englih Language · 1884 · p. 409

sol, a. Being or acting without another; single; only; alone; solitary. (Law.) Unmarried. — Sole/ly, adv. Singly; alone; only. — Solo, n. (Mus.) A tune, air, or strain, played by a single instrument, or sung by a single voice. — Soloist, -lo-ist, n. One who sings or plavs, etc.