branch : An oligomer molecule or polymeric offshoot from a macromolecular chain. (en)
Branching index: A parameter, , characterizing the effect of long-chain branches on the size of a branched macromolecule in solution and defined as the ratio of the mean-square radius of gyration of a branched molecule, , to that of an otherwise identical linear molecule, , with the same relative molecular mass in the same solvent and at the same temperature: (en)
branched chain: A chain with at least one branch point intermediate between the boundary units. (en)