an internal growth of bone. [ < endo-prefix and comb. form + ancient Greek ὀστέον bone (see osteo-comb. form) + -osissuffix, after exostosisn. or its etymon Hellenistic Greek ἐξόστωσις; compare ectostosisn. at ecto-comb. form.]
ΚΠ
1870 G. RollestonForms Animal Life 38 Ossified both by ectostosis and Endostosis.