noun, noun which may take the genitive case particle 'no'
once a month; monthly
Casual abbreviation of 月に一回 (once a month). Used in schedules, habits, or describing frequency.
この会議は月一で開かれます。
This meeting is held once a month.
月一のペースで映画を見に行く。
I go to see a movie about once a month.
noun
10% monthly interest
Slang from the consumer finance industry; 月一 (つきいち) refers to a monthly interest rate of 10%. Not used in general conversation.
闇金では月一の利息を取られることもある。
With loan sharks, they sometimes charge 10% monthly interest.
The full phrase meaning 'once a month'; 月一 is a casual abbreviation of this.
Similar abbreviation for 'once a week'. 月一 follows the same pattern.
Abbreviation of 月に一回 (つきにいっかい, 'once a month'), formed by taking the first character of 月 (つき) and 一 (いち). The pattern is productive for other time units (e.g., 週一, 年一).