expiration date

Noun

 * 1) A date by which an object either should not be used or loses its value, depending upon the item.

Usage notes
An expiration date when applied to edibles is the last date the maker (for prepared goods) or packager (for fresh goods) believes the product is still fresh and safe to eat. For manufactured items (e.g. batteries) it is usually the latest date when the product will provide the same level of performance as when it was first made. For pharmaceuticals and other drugs, it is the latest date when the product is expected to remain reasonably safe and effective. Note that these are estimates and the product may still be valid for a short time after and that a product, can, through improper storage, become unusable before the expiration date.

In the case of a financial instrument (like a futures contract), it is the last date when the item can be redeemed or is effective; after this date it becomes worthless. In the case of a contract, it is the final date that the contract is in effect.