pol|y|bro|mi|nat|ed biphenyl

pol|y|bro|mi|nat|ed biphenyl «_POL ee BROH muh _NAY tihd»,

any one of a group of poisonous and persistent chemicals related to the polychlorinated biphenyls, used as a fire retardant and additive to plastics, and regarded as a dangerous contaminant. Abbr: PBB (no periods).