ˈtenyələ̇n noun
( -s )
Etymology: New Latin tenuifolium (specific epithet of Helenium tenuifolium ) (from Latin tenuis thin + folium leaf) + -lin (as in helenalin ) — more at blade
: a crystalline sesquiterpenoid lactone C 17 H 22 O 5 obtained from plants of the genus Helenium (as H. tenuifolium )