What could be nicely defined, top or bottom, by radius (8)
I believe the answer is:
cylinder
'radius' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'what could be nicely defined top or bottom' is the wordplay.
'what could be' is an anagram indicator.
'top' says to take the initial letters.
'bottom' indicates one should take the final letters.
The initial letter of 'defined' is 'd'.
The final letter of 'or' is 'r'.
'nicely'+'d'='nicelyd'
'nicelyd' anagrammed gives 'cylinde'.
'cylinde'+'r'='CYLINDER'
'by' is the link.
Can you help me to learn more?
(Other definitions for cylinder that I've seen before include "Swiss-roll shape" , "Long round shape" , "Long, round figure" , "Piston chamber in a car" , "Chamber in motor" .)