endometriosis /ˌɛndoʊˌmiːtɹiˈoʊsɪs/ noun1 •A generally painful condition characterised by the presence of endometrial-like tissue in places other than the lining of the uterus; an instance of such tissue being present.The cyclic changes characterizing endometrioses are particularly apparent in endometriosis of the bladder. — 1934 formsendometrioses