A note played a semitone lower than a natural, denoted by the symbol ♭ placed after the letter representing the note (e.g., B♭) or in front of the note symbol (e.g. ♭♪).
3
A flat tyre/tire.
4
(in the plural) A type of ladies' shoes with very low heels.
She liked to walk in her flats more than in her high heels.