biphenyls Definition

a white crystalline hydrocarbon C6H5·C6H5 used especially as a heat-transfer medium and in organic synthesis; also : a derivative of biphenyl

any of several compounds that are similar to polychlorinated biphenyls in environmental toxicity and in structure but that have various hydrogen atoms replaced by bromine rather than chlorine —called also PBB

any of several compounds that are produced by replacing hydrogen atoms in biphenyl with chlorine, have various industrial applications, and are toxic environmental pollutants which tend to accumulate in animal tissues —called also PCB