a (music) In a higher pitch than is correct or desirable.
n (music) The symbol ♯, placed after the name of a note in the key signature or before a note on the staff to indicate that the note is to be played a semitone higher.
n (music) A note that is played a semitone higher than usual; denoted by the name of the note that is followed by the symbol ♯.
n (music) A note that is sharp in a particular key.
n (music) The scale having a particular sharp note as its tonic.
n (context|usually|in the|_|plural) Something which is sharp.
n (medicine) A hypodermic syringe.
n (medicine|dated) A scalpel or other edged instrument used in surgery.