F

F is pitch class 5 — a perfect fourth above C (five semitones). It is a natural letter-name, the white key between E and F♯/G♭, often Fa in movable solfège.

From C it is the first perfect consonance that is not a unison or octave in this counting. Chromatically it sits one semitone above E and one below F♯/G♭.

In major-triad grammar F is the root of F major (F–A–C), the major third of D♭/C♯ major when spelled as E♯’s partner in that triad’s third, and the perfect fifth of B♭ major (B♭–D–F). Alone it stays a pitch class. Key character waits on a closed major triad in the vessel.

Also known as F natural · Fa