ex‧pir‧y [uncountable] British English
the end of a period of time during which an official document can legally be used, or the end of a period of authority [= expiration American English]
the formal expiry of the presidential term in September
Only seven minutes remained before the expiry of the noon deadline.
the date after which something is not safe to eat or can no longer be used [= expiration date American English]
Check the expiry date on your passport.
Eggs must be marked with an expiry date that is ten days from the date of packing.