Princeton's WordNet

1. bacillus, B(noun)

   aerobic rod-shaped spore-producing bacterium; often occurring in chainlike formations; found primarily in soil

   Synonyms:
   barn, vitamin B, atomic number 5, group B, vitamin B complex, boron, type B, bacillus

2. B-complex vitamin, B complex, vitamin B complex, vitamin B, B vitamin, B(noun)

   originally thought to be a single vitamin but now separated into several B vitamins

   Synonyms:
   boron, barn, vitamin B, atomic number 5, group B, vitamin B complex, type B, bacillus

3. boron, B, atomic number 5(noun)

   a trivalent metalloid element; occurs both in a hard black crystal and in the form of a yellow or brown powder

   Synonyms:
   barn, vitamin B, atomic number 5, group B, vitamin B complex, boron, type B, bacillus

4. Bel, B(noun)

   a logarithmic unit of sound intensity equal to 10 decibels

   Synonyms:
   barn, vitamin B, atomic number 5, group B, vitamin B complex, boron, type B, bacillus

5. barn, b(noun)

   (physics) a unit of nuclear cross section; the effective circular area that one particle presents to another as a target for an encounter

   Synonyms:
   barn, vitamin B, atomic number 5, b, group B, vitamin B complex, boron, type B, bacillus

6. B, b(noun)

   the 2nd letter of the Roman alphabet

   Synonyms:
   barn, vitamin B, atomic number 5, group B, vitamin B complex, boron, type B, bacillus

7. B, type B, group B(noun)

   the blood group whose red cells carry the B antigen

   Synonyms:
   barn, vitamin B, atomic number 5, group B, vitamin B complex, boron, type B, bacillus