amyl (n.)

hydrocarbon radical, 1850 (amyle), from Latin amylum "starch," from Greek amylon "fine meal, starch," noun use of neuter of adjective amylos "not ground at the mill," that is, "ground by hand," from a- "not" (see a- (3)) + myle "mill" (from PIE root *mele- "to crush, grind"). So called because first obtained from the distilled spirits of potato or grain starch (though it also is obtained from other sources). In 16c. English amyl meant "starch, fine flour."