expiration date; validity period
Refers to the date until which something is valid, such as a credit card, medicine, coupon, or contract.
このクーポンの有効期限は来月までです。
This coupon is valid until next month.
薬の有効期限を確認してください。
Please check the expiration date of the medicine.
This coupon has expired.
Please check the expiration date before taking the medicine.
Members can extend their validity period by one year.
Please use it within the validity period.