The Collaborative International Dictionary
Aphthae \Aph"th[ae]\, n. pl. [L., fr. Gr. ? (mostly in pl. ?, Hipp.) an eruption, thrush, fr. ? to set on fire, inflame.] (Med.) Roundish pearl-colored specks or flakes in the mouth, on the lips, etc., terminating in white sloughs. They are commonly characteristic of thrush.
n. (plural of aphtha English)