norethisterone UK /nɔː.ɹɛˈθɪ.stə.ɹəʊn/US /ˌnɔɹ.əˈθɪ.stəˌɹoʊn/ noun1 •A synthetic steroid hormone, 19-nor-17α-ethynyltestosterone (C₂₀H₂₆O₂), which has actions similar to those of progesterone and is used chiefly for contraception.
