The phrase "expiration timer" refers to a countdown or a clock that tells you when something will end or expire. It's like a reminder to let you know when a certain time limit is up.
Sentences with «expiration timer»
It's unclear at the moment how that feature would work, though developers are reportedly considering expiration timers. (slate.com)
Step # 5: Tap on the timer icon seen at the top right corner of your phone screen and set up chat expiration timer. (indabaa.com)
Facebook already offers a «Secret» encrypted messaging feature that includes an Unsend expiration timer. (techcrunch.com)