Meaning of “defrost” - Learner’s Dictionary

defrost

verb [ I, T ] uk us /ˌdiːˈfrɒst/
FOOD

If food defrosts, it becomes warmer after being frozen, and if you defrost it, you make it become warmer after being frozen:

You need to defrost the fish before you can cook it.
FREEZER

If you defrost a fridge or freezer (= machines that keep food cold), you make them warmer and remove the ice, and if they defrost, they become warmer and the ice melts.

(Definition of “defrost” from the Cambridge Learner’s Dictionary © Cambridge University Press)