Apple’s unlikely to last long after this consumer device makes an impression (7)
I believe the answer is:
incisor
'apple's unlikely to last long after this consumer device makes an impression' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
This is all the clue.
(Other definitions for incisor that I've seen before include "oral equipment" , "Cutting tooth" , "carnivore requires?" , "Canine" , "something with bite" .)