The period until which something may be used; an indicated expiry/use-by date on food, medicine, or other products after which use is not recommended or guaranteed.
牛乳のパックに使用期限が明記してあるので、必ず確認してください。
The milk carton has the use-by date printed on it, so be sure to check it.
この薬は使用期限が切れているので、捨てた方がいい。
This medicine is past its expiry date, so you should throw it away.
使用期限と賞味期限は意味が異なるので注意が必要だ。
Be careful, as 'use-by date' and 'best-before date' have different meanings.