noun
birth month
Refers to the month in which someone was born. Used in contexts like school year grouping, astrology, or seasonal associations.
生まれ月によって、同じ学年でも年齢が違うことがある。
Depending on one's birth month, ages can differ even within the same school year.
誕生月 also means 'birth month' but is slightly more formal and often used in official or written contexts, while 生まれ月 is more colloquial.
Compound of 生まれ (umare, 'birth') and 月 (tsuki, 'month'), with rendaku voicing of つき to づき.