In musical notation, a key signature is a set of sharp or flat symbols placed together on the staff. Key signatures are generally written immediately after the clef at the beginning of a line of musical notation, although they can appear in other parts of a score, notably after a double barline.
A key signature designates notes that are to be played higher or lower than the corresponding natural notes and applies through to the end of the piece or up to the next key signature. A sharp symbol on...