A part of a molecule having one incomplete ring of structure (10)
I believe the answer is:
anatomical
'of structure' is the definition.
(I've seen this before)
'a part of a molecule having one incomplete ring' is the wordplay.
'a' becomes 'an'.
'part of a molecule' becomes 'atom' ('atom' is part of 'molecule').
'having one' becomes 'i' (I can't explain this - if you can you should give a lot more credence to this answer).
'incomplete' means to remove the last letter.
'ring' becomes 'call' (synonyms).
'call' with its last letter taken away is 'cal'.
'an'+'atom'+'i'+'cal'='ANATOMICAL'
Can you help me to learn more?
(Other definitions for anatomical that I've seen before include "structural details" , "Relating to bodily structure" , "Relating to studies of the body" , "Pertaining to bodily structure" .)