Component of cell made of metal, mostly, with part hiding hole (10)
I believe the answer is:
chromosome
'mostly with part hiding hole' is the definition.
The answer and definition can be both body parts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'component of cell made of metal' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found in the answer.
'metal' could be 'os' (Os is an example) and 'os' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for chromosome that I've seen before include "structure in cell" , "Gene carrier" , "this could be X or Y" , "Genetic structure" , "Structure carrying genes" .)