The Grand Staff using both bass clef on the bottom and treble clef on top allows for four octaves of notation, counting the two high ledger lines for Soprano C and two ledger lines below bass clef for Deep C. It is known as the grand staff because the two clef notation allows the notation of nearly all musical notes without many ledger lines or octave shifts such as 8va or 8vb. See musical staff for more information on staves in general. Soprano C is the C two octaves above Middle C. It is named because it is considered the high note of the soprano (although many, especially the coloratura soprano go much higher). ... Deep C is the C two octaves below Middle C, and is also named C2. ... In musical notation, the staff or stave is a set of five horizontal lines on which note symbols are placed to indicate pitch and rhythm. ...
Middle C is so named because it appears exactly in the middle between the bass and treble clefs. Middle C is not exactly in the middle of any keyboard instrument, including the piano. In music, the term middle C refers to the note C located between the staves of the grand staff, quoted as C4 in note-octave form. ...
Nearly all piano music is written on the grand staff, as is some choral music.
The musical staff can be thought of as a graph of pitch with respect to time; pitches are roughly given by their vertical position on the staff, and notes on the left are played before notes to their right.
Music on the staff is read from left to right: one note to the right of another means that it is to be played later; how much later depends on its note value and the tempo.
Exactly which notes are represented by which staff positions is determined by a clef placed at the beginning of the staff; the clef identifies a particular line as a specific note, and all other notes are determined relative to that line.