noun
Mondays and Fridays
Abbreviation of 月曜日と金曜日, used in schedules or when referring to days of the week in a compact form.
このジムは月金だけ営業しています。
This gym is open only on Mondays and Fridays.
月金の朝は電車が特に混む。
Trains are especially crowded on Monday and Friday mornings.