B2Pronunciation: /biː/Translate B | into French | into German | into Italian | into Spanish Definition of B abbreviation Belgium (international vehicle registration). bishop (used in recording moves in chess):Be5 black (used in describing grades of pencil lead):2B pencils bomber (in designations of US aircraft types):a B-52 symbol the chemical element boron. Physics magnetic flux density. B in other Oxford dictionaries Definition of B in the US English dictionary