Definition of sharp:
"I keep my knives sharp so that they don't slip unexpectedly while carving."
(v) :
Exactly; in a higher pitch than is correct or desirable
"I'll see you at twelve o'clock, sharp."
(n) :
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; a note that is sharp in a particular key
"frequently, transposition is harder to read because of all the sharps and flats on the staff."