:I'm nearly finished reading a British source that I think has a solid definition, which I'll eventually use to replace this.  (Actually, I hope to eventually find time to massively re-write nearly the entire article.)  Our first sentence is far too narrow (it doesn't encompass chocolates or chewing gum, both of which are "sweets" in British English and "candy" in American English).   
 :I'm still sorting out how to coordinate it with Confectionery.  (If you've got ideas, then please speak up. -)  Confectionery includes all candy, but also sweet pastries.  The line between the two is not firm; small pieces of baklava are "sweets" (or "candy") in parts of the Middle East, but they are always "pastry" in Western cultures.  
 :One possibility is three articles:  Confectionery (all sweets and sweet pastries) > Sweets (British use:  all non-pastry confections, from boiled sugar candy to chewing gum to chocolate bars) > Sugar candy (specifically the hard-sugar kinds of candies, not candy bars).  Another possibility is just one article, at Confectionery, that covers everything.