ˌekˌsäˈstōsə̇s noun
( plural exosto·ses -ōˌsēz)
Etymology: New Latin, from Greek exostōsis, from ex out of, out + osteon bone + -ōsis -osis — more at ex- , osseous
1. : a spur or bony outgrowth from a bone or the root of a tooth
2. : the formation of knots upon the surface of wood in trees