pīˈperəˌlēn, pə̇ˈp-; ˈpipər- noun
( -s )
Etymology: International Scientific Vocabulary piper idine + -ylene
: an oily diolefin hydrocarbon CH 3 CH = CHCH = CH 2 isomeric with isoprene formed in the cracking of petroleum and also made synthetically (as by exhaustive methylation of piperidine); 1,3-pentadiene