b 1 or B (bē)
n. pl. b's or B's also bs or Bs
1. The second letter of the modern English alphabet.
2. Any of the speech sounds represented by the letter b.
3. The second in a series.
4. Something shaped like the letter B.
5. B The second best or second highest in quality or rank: a mark of B on an English theme.
a. The seventh tone in the scale of C major or the second tone in the relative minor scale.
b. A key or scale in which B is the tonic.
c. A written or printed note representing this tone.
d. A string, key, or pipe tuned to the pitch of this tone.
7. B One of the four major blood groups in the ABO system. Individuals with this blood group have the B antigen on the surface of their red blood cells, and the anti-A antibody in their blood serum.
(click for a larger image)illuminated letter, The Book of Wonders
This 14th-century French manuscript chronicles the travels of Marco Polo.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.