# fifth

A fifth is the interval between the first and fifth
notes of a diatonic scale. A **perfect
fifth** (often abbreviated P5) is a fifth spanning seven half-notes
(semitones). For example, the interval from C to G is a perfect fifth, as
the note G lies seven semitones above C, and there are five stave positions
from C to G. **Diminished fifths** and **augmented fifths** span the same number of stave positions, but consist of a different number
of semitones (six and eight, respectively).

See also open fifth and parallel fifths.