episiotomy UK /ˌɛpəsaɪˈɒtəmiː/US /əˌpiːziːˈɒtəmiː/ noun1 •A surgical incision through the perineum made to enlarge the vagina and assist childbirth.The following eight hours were the worst of my life that haven't ended in an episiotomy. — 2011 formsepisiotomies