A memorable lay one can't get out of head? (7)
I believe the answer is:
earworm
'a memorable lay one can't get out' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'head?' is the wordplay.
I cannot quite see how this works, but
'head?' could be 'ear' (I have seen 'Head of corn' mean 'ear' so perhaps 'head' could also mean 'ear') and 'ear' is found within the answer.
The remaining letters 'worm' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for earworm that I've seen before include "Repetitive strain" , "Irritatingly catchy tune" .)