The Collaborative International Dictionary of English v.0.48:
Amenorrhoea \A*men`or*rhoe"a\, Amenorrhea \A*men`or*rhe"a\ \ \ ([.a]*m[e^]n`[o^]r*r[=e]"[.a]), n. [Gr. 'a priv. + mh`n month + "rei^n to flow: cf. F. am['e]norrh['e]e.] (Med.) Pathological or physiological absence of menstruation. [1913 Webster + AS]WordNet (r) 3.0 (2006):
amenorrhoea n 1: absence or suppression of normal menstrual flow [syn: amenorrhea, amenorrhoea, amenia]