月げっ経けいげっけいCommon wordFreq.FrequencyTop 50,000Meanings1nounmenstruation; menstrual periodStandard medical and everyday term for menstruation.月げっ経けいが始はじまったのは12歳さいのときです。I started menstruating when I was 12.月げっ経けい周しゅう期きは個こ人じん差さ