Is a ton this weight? (7)
I believe the answer is:
hundred
'is a ton this weight?' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for hundred that I've seen before include "C in Roman numerals" , "Ancient division of a county" , "so many others" , "See 19" , "Old subdivision of a shire or county" .)