(β).A prefix having meanings analogous to those of α.(1) It indicates (a) the position of a substituent atom or radical in a compound; (b) the second position in a naphthalene ring; or (c) the attachment of a chemical unit to the side chain of an aromatic compound.(2) It refers to a secondary allotropic modification of a metal or compound.(3) It designates a type of radioactive decay.See Beta Particle.