A coarse woollen cloth from Tripoli.

(mineralogy) A tetragonal-pyramidal mineral containing calcium, hydrogen, iron, oxygen, and phosphorus.

(medicine) A congenital oral anomaly in which the lingual frenulum is unusually short and thick, decreasing mobility of the tongue and affecting eating, speech, etc.

(mathematics) An important statement about surfaces in differential geometry, connecting their geometry (in the sense of curvature) to their topology (in the sense of the Euler characteristic).