Mob under a man in charge making scientific measurement (6,4)
I believe the answer is:
atomic mass
'scientific measurement' is the definition.
The answer and definition can be both human attributes as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'mob under a man in charge' is the wordplay.
'mob' becomes 'mass' (I can't justify this - if you can you should give a lot more credence to this answer).
'under' is a charade indicator (letters next to each other) (in a down clue, some letters go below others).
'man' becomes 'tom' (man's name).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'a'+'tom'+'ic'='atomic'
'mass' after 'atomic' is 'ATOMIC MASS'.
'making' acts as a link.
Can you help me to learn more?