Cacao vs. cocoa is a great debate in the health food community; it's full of assumptions from either side, not all of which are based in fact. So here we'll lay out the full answer to the query: is cacao the same as cocoa?
In terms of physical origins, whether you say cacao or cocoa, it's material from the same tropical plant: Theobroma cacao. The plant has been used for millennia in its native Central & South America, but it was only introduced into the global lexicon about five centuries ago. When the Spanish explorers arrived in the Caribbean at the end of the 15th century, one of the first native foods they discovered and brought back to the Spanish court were cacao seeds. The seeds needed a name, so they took the Aztec's word for beverages made with cacao, cacahoatl, and simplified it for Spanish. Cacahoatl became "cacao." Then again when the British and French began consuming cacao, it’s believed that a misspelling caused the slight name change, making it "cocoa."
When Swedish scientist Carl Linnaeus gave the species its scientific name in the 18th century, he tied the word cacao to the tree itself. But the cacao-based products we consume are far removed from their roots, even so far as being tied to the English phrase rather than the Spanish one. Over time, beyond the language difference, the use of the two terms diverged, as well. Using “cacao” began to signify that a product was closer to its origin as a fruit from the Americas, while “cocoa” was a world commodity and a sweet drink for winter days. But over the past decade, advertisers have gotten hip to the connotations of one term over the other.
Merely seeing "cacao" vs "cocoa" doesn't legally indicate anything about the product, and may just be a word choice based on cultural conditioning. The English "cocoa" is as much of an import into some parts of the world as the original cacao seeds were to Europe.
In parts of Asia and Central & South America, "cocoa" is akin to chocolate, while "cacao" is a crop or fruit from a tree, if it has meaning at all. Hot cocoa mix was a historically affordable luxury import, spreading the flavor of chocolate around the world. In this modern role reversal, companies now use "cacao" to indicate an import with health benefits, framed to be praised and worshipped as it once was. Manufacturers want consumers to believe that their product is the least-processed and most healthy option, and they choose cacao over cocoa to signify this.
As consumers, we need to keep this lack of difference in mind. In the end, cacao and cocoa are the same thing, but the implications evoked by the use of one or the other may be slightly different. "Cocoa" became famous along with its language, English, while the formerly regional term of "cacao" is slowly coming to the forefront, just as it did centuries ago.