To a point, it's heavy (3)
I believe the answer is:
ton
'heavy' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'to a point' is the wordplay.
'a point' becomes 'n' (N is an example).
'to'+'n'='TON'
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for ton that I've seen before include "Twenty cwt" , "1000 kilos" , "People of fashion" , "Weight - fashion (French)" , "Unit of weight equivalent to 2240 pounds" .)