Fnoun
us/ef/plural F’s or FsF noun (LETTER)
[ C ] plural F’s, Fs, f’s or fs also f the sixth letter of the English alphabet
F noun (MUSICAL NOTE)
music [ C/U ] plural F’s or Fs in Western music, the fourth note in the scale (= series of notes) that begins on the note C, or a set of notes based on this note
F noun (MARK)
[ C ] plural F’s or Fs a mark given for an exam, a course, or a piece of work which shows that your work has failed to meet the lowest acceptable standard:
I’m giving you an F if your paper isn’t in by Thursday.
F noun (TEMPERATURE)
[ U ] abbreviation for Fahrenheit:
Yesterday the temperature was 90°F.