B
     n 1: the blood group whose red cells carry the B antigen [syn: {type
          B}, {group B}]
     2: aerobic rod-shaped spore-producing bacterium; often
        occurring in chainlike formations; found primarily in soil
        [syn: {Bacillus}, {Bacilli}]
     3: originally thought to be a single vitamin but now separated
        into several B vitamins [syn: {B-complex vitamin}, {B
        complex}, {vitamin B complex}, {vitamin B}, {B vitamin}]
     4: a trivalent metalloid element; occurs both in a hard black
        crystal and in the form of a yellow or brown powder [syn:
        {boron}, {atomic number 5}]
     5: a logarithmic unit of sound intensity equal to 10 decibels
        [syn: {bel}]
     6: (physics) a unit of nuclear cross section; the effective
        circular area that one particle presents to another as a
        target for an encounter [syn: {barn}]
     7: the 2nd letter of the Roman alphabet
Source: WordNet® 2.0