benzo[a]pyrene

noun
ben·​zo·​[a]·​py·​rene | \ ˌben-zō-ˌā-ˈpī(ə)r-ˌēn, -zō-ˌal-fə-, -pī-ˈrēn How to pronounce benzo[a]pyrene (audio) \
variants: also 3,4-benzpyrene \ -​benz-​ˈpī(ə)r-​ˌēn, -​ˌbenz-​pī-​ˈrēn How to pronounce 3,4-benzpyrene (audio) \

Medical Definition of benzo[a]pyrene

: the yellow crystalline highly carcinogenic isomer of the benzopyrene mixture that is formed especially in the burning of cigarettes, coal, and gasoline