The Collaborative International Dictionary of English v.0.48:

Menorrhagia \Men`or*rha"gi*a\, n. [NL., fr. Gr. mh`n month + ?
   to break.] (Med.)
   (a) Profuse menstruation.
   (b) Any profuse bleeding from the uterus; Metrorrhagia.
       [1913 Webster]

WordNet (r) 3.0 (2006):

menorrhagia
    n 1: abnormally heavy or prolonged menstruation; can be a
         symptom of uterine tumors and can lead to anemia if
         prolonged [syn: menorrhagia, hypermenorrhea]