It can be confusing to talk about chocolate. Here are definitions of some common terms:
cacao: the plant and seeds from which chocolate is made, and the earliest raw form of chocolate, before any other ingredients are added to produce drinking chocolate or eating chocolate.
cocoa: a fat-free powder formed when cacao is pressed into hard cakes with the cocoa butter removed, and then ground into powder.
hot cocoa or hot chocolate: drinking chocolate, made from cocoa or eating chocolate melted in hot water or milk.
dark chocolate: eating chocolate made with more than 50% cacao. In the United States, eating chocolate or baking chocolate containing 70% or more cacao or chocolate liquor is classified as bittersweet chocolate, but the trend toward darker eating chocolate has made this term less common.
milk chocolate: eating chocolate made with milk, often less than 30% cacao, but sometimes as much as 60%. In the United States, milk chocolate must contain at least 10% chocolate and 12% whole milk to be labeled "milk chocolate."
white chocolate: a cocoa butter product with no cocoa or chocolate liquor. White chocolate must be made with at least 20% cocoa butter to be labeled as "white chocolate" in the United States. Prior to 2002, the labeling rules were different, and some supposed white chocolate products were made entirely with other vegetable oils.
