johnny (Noun) — Contraceptive device consisting of a sheath of thin rubber or latex that is worn over the penis during intercourse.
johnny (Noun) — A gown with a back opening closed with snaps or ties, worn by hospital patients.
johnny (Noun) — 'Johnny' was applied as a nickname for Confederate soldiers by the Federal soldiers in the American Civil War; 'greyback' derived from their grey Confederate uniforms.