PBB

Chemistry.
  1. any of the highly toxic and possibly carcinogenic aromatic compounds consisting of two benzene rings in which bromine takes the place of two or more hydrogen atoms: used as a fire retardant and additive for plastics.

Origin of PBB

p(oly)b(rominated) b(iphenyl)
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018