ˈpentə̇l noun
( -s )
Etymology: International Scientific Vocabulary penta- + -yl
: any of eight isomeric alkyl radicals C 5 H 11 derived from the three pentanes by removal of one hydrogen atom: as
a. : the normal radical CH 3 (CH 2 ) 3 CH 2 − — called also amyl, n-amyl, n-pentyl
b. : isopentyl
c. : neopentyl