ˌheləˈnalə̇n, -nāl- noun
( -s )
Etymology: helen- (from New Latin Helenium, genus name of the sneezeweed Helenium autumnale ) + -al- (from New Latin autumnale, specific epithet of the sneezeweed Helenium autumnale ) + -in
: a poisonous bitter crystalline compound C 15 H 18 O 4 that is the active principle of sneezeweed