amenorrhea Syllabification: (a·men·or·rhe·a)Pronunciation: /āˌmenəˈrēə/ (British amenorrhoea)Definition of amenorrhea noun an abnormal absence of menstruation. Origin: early 19th century: from a-1 'without' + meno- + -rrheaamenorrhea in other Oxford dictionaries Definition of amenorrhea in the British & World English dictionary