Definition of double flat in English:

double flat

noun

  • 1A sign placed before a musical note to indicate that it is to be lowered two semitones.

    • ‘The sharp raises the note before which it is placed by one semitone; the flat lowers it by one semitone; the double sharp and double flat respectively raise and lower it by a whole tone; the natural cancels any other accidental.’
    1. 1.1A musical note marked by a double flat or lowered two semitones.
      • ‘Gurney knows it well - witness the opening line of ‘Sleep’ (D flat-F; D flat-B double flat).’