n. (also b) (pl. Bs or B's)
1 the second letter of the alphabet.
2 Mus. the seventh note of the diatonic scale of C major.
3 the second hypothetical person or example.
4 the second highest class or category (of roads, academic marks, etc.).
5 Algebra (usu. b) the second known quantity.
6 a human blood type of the ABO system.
Phrases and idioms:
B film a supporting film in a cinema programme.
1 Chem. the element boron.
2 Physics magnetic flux density.
abbr. (also B.)
4 black (pencil-lead).
Useful english dictionary. 2012.