What is Cocoa ?
Cocoa is (noun) 1. a brown chocolate powder ground from the seeds of a tree, used for making a drink There’s a tin of cocoa on the shelf next to the cooker. Add cocoa powder to icing sugar to make chocolate icing. 2. a drink made with cocoa powder and hot water or milk I’ll warm up some milk to make cocoa. He always has a cup of cocoa before going to bed. (NOTE: no plural)
source: Easier English, Student Dictionary Upper Intermediate Level