The article you linked talks about cacao being the raw bean and cocoa being the processed powder. It also says you can get cacao from chocolate bars. I don't think there is a difference between cocoa powder and cacao powder.

> “Think of cacao, cocoa and chocolate like a pipeline,” says Fazio. “Cacao [fruit] grows from a tree and is raw and unprocessed. It’s the precursor to cocoa, and cocoa is the precursor to chocolate.”

> “The taste of cacao is earthy and bitter, and it has a grittier mouthfeel than chocolate,” says Fazio. “Cocoa powder tastes more like chocolate than cacao, but it doesn’t have a creamy mouthfeel either because most of the cocoa butter has been removed.”

> Some experts use “cacao” for the pods, beans and ground-up contents of the beans, reserving “cocoa” for the powder left after pressing the fat out of the ground beans (1Trusted Source).