Understand the difference record margin had in cuts (12)
I believe the answer is:
discriminate
'understand the difference' is the definition.
I can't judge whether this defines the answer.
'record margin had in cuts' is the wordplay.
'record' becomes 'disc' (eg a CD, compact disc).
'margin' becomes 'rim' (both can mean something's edge).
'had' means one lot of letters go next to another.
'in cuts' becomes 'inate' (I can't justify this - if you can you should give a lot more credence to this answer).
'disc'+'rim'+'inate'='DISCRIMINATE'
Can you help me to learn more?
(Other definitions for discriminate that I've seen before include "Show taste" , "Recognise a distinction" , "Understand the difference (between)" , "Unjustly treat a group as different" , "Single out" .)