Why was "tantrum" trending last week?
from Latin labia, plural of labium "lip" (see lip (n.)). Specifically of the folds on either side of the vulva from 1630s (labia pudendi).
labium la·bi·um (lā'bē-əm)
n. pl la·bi·a (-bē-ə)
A lip or lip-shaped anatomical structure.
Any of four folds of tissue of the female external genitalia.