any of several North American plants of the genus Trillium, esp T. erectum, whose tuber-like roots were formerly used by the Native Americans as an aid in childbirth: family Trilliaceae
birthroot in American English
(ˈbɜːrθˌruːt, -ˌrut)
noun
1. Also called: birthwort, purple trillium
a trillium, Trillium erectum, the roots of which were formerly used in medicine as an astringent