Pedal point
In harmony, a pedal point is a note that is sustained throughout a harmonic progression. It can be used to prolong a harmony. Most of the time, a pedal point is a bass note.1
Pedal points can be notated by writing ped beside the chord that initiates the pedal.
The term "pedal" comes from the pedals on an organ which would be utilized for this technique.
Examples
Example 1
In this case, the pedal point is C which is used underneath the chords C F G7 C. (This may be notated as C F/C G7/C C .)

Example 2
