Abnormally light or infrequent menstruation

Wiktionary Word definitions in Wiktionary
alt. infrequent or light menstrual periods in women of child-bearing age. n. infrequent or light menstrual periods in women of child-bearing age.

Wikipedia Word definitions in Wikipedia
Oligomenorrhea (or oligomenorrhoea ) is infrequent (or, in occasional usage, very light) menstruation . More strictly, it is menstrual periods occurring at intervals of greater than 35 days, with only four to nine periods in a year. Also, menstrual periods ...

WordNet Word definitions in WordNet
n. abnormally light or infrequent menstruation