In stanard Western musical notation, the staff is a set of five horizontal lines and four spaces, on which note symbols are placed to indicate their pitch. The pitches indicated by the vertical position of notes on the staff are relative to a fixed pitch that is determined by the placement of a symbol called a clef at the left-hand side of the staff. For example, the treble clef, also known as the G clef fixes the second line (counting upwards from the bottom line) as the pitch G, more specifically, the G that is the first G above 'middle C'. The lines and spaces are numbered from bottom to top; the bottom line is the first line and the top line is the fifth line.