1. Various very stable chlorinated organic chemicals that can be dangerous environmental pollutants
   - PCB

Encyclopedia: Polychlorinated biphenyl

• unsyllabic
• unsyllabled
• unsymbolic
• unsymmetric
• unsymmetrical
• unsymmetrically
• unsympathetic
• unsympathetically
• unsympathising
• unsympathizing
• unsynchronised
• unsynchronized
• unsynchronous
• exorciser
• exorcism
• exorcist
• exorcize
• exordial
• exordium
• exoskeletal
• exoskeleton
• exosphere
• exostosis
• exoteric
• exotherm