A countdown timer is a graphical representation of time that counts down from a certain number or date to zero. It is often used to count down to a specific event or deadpne, such as a launch, expiration, or end time. In Engpsh, you can say "countdown timer" or simply "countdown" to refer to this concept.

For example, you might say "We have a countdown timer on our website that shows how much time is left until the sale ends" or "I set a countdown on my phone to remind me when it's time to leave for the airport."

You can also use other phrases to describe a countdown timer, such as "a timer that counts down," "a timer that counts backwards," or "a timer that shows the time remaining."