n. — Food
a bar of sweetened chocolate.
Type: 5. Frequency — Chocolate bar refers to an oblong strip of sweetened chocolate, sometimes containing other ingredients such as nuts or caramel. The term is often contrasted with "candy bar", the more popular variant in the US. In that country, trade names such as "Mars bar", "Snickers" or "Hershey's bar", which are also used in Canada, appear to be most popular. Boberg (2005: 48) notes that chocolate bar is one of the strongest lexical variables in his study of the linguistic border between Canada and the US; he also notes that the variant is a Canadianism not found in British English and not found very frequently in the US. While Chart 1 confirms Boberg's assessment of the term in the US, it also shows that in the UK the term may be quite widespread. In Newfoundland, the primary variant is simply "bar" (Boberg 2005: 37), which may also be found in parts of PEI and Nova Scotia, though not in New Brunswick (Boberg 2008: 69-70).
(see COD-2, s.v. "candy bar")
Images:

Chart 1: Internet Domain Search, 21 Dec. 2015 
Chart 2: Internet Domain Search, 21 Dec. 2015