bioequivalent /bī′ō·ikwiv″ələnt/ [Gk, bios + L, aequus, equal, valere, to be strong] , 1. (in pharmacology) pertaining to a drug that has the same effect on the body as another drug, usually one nearly identical in its chemical formulation but possibly requiring a different amount to see the same effect. 2. going in and out of the body at the same rate. −bioequivalence, n.