Packers seen on the moon? (7)
I believe the answer is:
craters
'packers' is the definition.
Although both the answer and definition are plural nouns, I don't see how they can define each other.
'on the moon?' is the wordplay.
I cannot really understand how this works, but
'on' could be 'at' (I've seen this in other clues) and 'at' is found in the answer.
This explanation may well be incorrect...
'seen' acts as a link.
Can you help me to learn more?
(Other definitions for craters that I've seen before include "Shell-holes" , "Depressions" .)