Limitations of costly confectionery in US (5)
I believe the answer is:
candy
This clue could be a double definition.
'limitations of costly confectionery' is the first definition.
'candy' can be an answer for 'confectionery' (candy is a kind of confectionery). I'm not sure about the 'limitations of costly' bit.
'us' is the second definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for candy that I've seen before include "Sweet (US)" , "Girl's name (diminutive)" , "Sugary sweet" , "Crystallised sugar; US sweets" , "American sweets" .)