labia (n.)

in anatomy and zoology, "lips or lip-like parts," a Modern Latin use of Latin labia "lips," plural of labium "lip" (see lip (n.)). Specifically as "the folds on either side of the vulva" (labia pudendi) from 1630s; further classified as labia majora (the outer folds, 1813; the singular is labium majus) and labia minora (inner folds, 1781; the singular is labium minus). The lips of the mouth are labium superior (upper) and labium inferiore (lower).