‖Ex′os‐to″sis (?), n. [NL., fr. Gr. �; � out + � bone: cf. F. exostose.] 1. (Med.) Any protuberance of a bone which is not natural; an excrescence or morbid enlargement of a bone. Coxe.
2. (Bot.) A knot formed upon or in the wood of trees by disease.