2.3 The great staff
We can call a staff with a treble clef a treble staff for short, and a staff with a bass clef a bass staff. And if we place the former above the latter and insert an additional line in between, we create what is called the great (or grand) staff as shown in Example 6.
There are two points about the great staff. Firstly, it demonstrates the relationship between the bass and treble staves. Secondly, the additional line at the midway point is the line for middle C. The central importance in the great staff of the middle C line is one reason for middle C’s name, and its position roughly halfway along the keyboard is another.