As it stands, the first note in Example 2 could be any pitch we care to choose.
Example 2 (repeated)
So if we wish to specify a particular pitch or series of pitches we need some sort of guide – a sign that will enable us to indicate the specific pitch. That sign is supplied by a clef (from the Latin, clavis, meaning ‘key’). From the eleventh century onwards, several Roman letters, including c and f, were used systematically for clefs, with g subsequently becoming increasingly common. In a stylised form, g, with flamboyant curls and flourishes, is still used as the treble or G clef, and signifies that a note placed on the second line from the bottom is G (see Example 3).
And this is not any G, but specifically the one above middle C. (We’ll come to an explanation of middle C in a moment.)
As Example 4 shows, the other notes are named with letters from the alphabet, A–G, with A returning after G has been reached.
Notice that as the notes are placed higher and higher up the staff, the pitch becomes higher and higher as well. Notice too that we read music from left to right, and with a whole page of music, from top to bottom. This reflects the way we read words in western culture.
The letter, f, in a stylised form and in a mirror image, is now used as the bass or F clef.It signifies that a note placed on the second line from the top is F, and specifically the F below middle C (see Example 5).