/ Dictionary / Index P PCB: Meaning and Definition of Find definitions for: PCB Pronunciation: [key] a family of highly toxic chemical compounds consisting of two benzene rings in which chlorine takes the place of two or more hydrogen atoms: known to cause skin diseases and suspected of causing birth defects and cancer. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. PC PC board Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language