"Theobroma cocoa" is the scientific name of the tropical cocoa tree, which in greak language means: "Gods food".
Cocoa is the product that results of the cocoa beans fermentation and drying, and it is the basic componet of chocolate.   

There are three main varieties of cocoa:
Creole or native cocoa: it is the genuine cocoa, and was named that way by the spaniards on their arrival to Mexico. It is a well known high quality cocoa, with a limited tannin content, kept for the finest chocolates productions. The cocoa bean has a thin husk. Once it is roasted it is soft and aromatic.  
Foreign or rural cocoa: it comes from the high Amazonia. It is a nomal cocoa, with higher tannin. Its bean has a thick husk, and it is tough and little aromatic. In order to neutralize its imperfections, the roasting must be intense, where taste and aroma comes from.
Hybrid cocoas, emphasizing the trinitarian cocoa: a crossing between creole and foreign cocoa, although its quality is closer to the second. This way, it inherited the robust quality of the foreign cocoa and the delicate taste of the creole cocoa.

Cocoa fruit has a bumpy peel. It is filled with a viscous, sweet, edible rosy pulp, which conteins from 30 to 50 long beans (white and fleshy), placed in lines in the trellis of that pulp. Cocoa beans have the same almonds shape, and their taste in crude is very bitter.

Mayan people created a bitter potion called Chocolha, made of cocoa beans, that was exclusively drunk by kings and nobles, and it was also used to bring solemnity to certain holy rituals. They used this potion with therapeutic purpose. Mayan doctors prescribed cocoa consumption both as estimulant and painkiller. Warriors used to have it as a restorative drink, and cocoa butter was used as oinment for healing the wounds. It was also used as currency...  
However, the Cocoa drink that Cortes had drunk in gold glasses during  the banquets organized in his honour by Moctezuma was very different to what we are used to drink nowadays. The Xocolatl, that was its name in that time, was a bitter water. The Aztecs mixed pepper with the roasted and ground cocoa beans, and then added corn flour to it.
The Aztecs knew that a mug of drinking xocolatl eliminated tiredness and stimulated physical and mental capacities. For Aztecs, xocolatl was a source of spiritual wisdom, energy and sexual power. It was highly prized as an aphrodisiac product, and was one of the favourite drinks in weddings. It was a drink kept for the elite, and was also called liquid gold, since the cocoa beans were used as local currency too. According to scientists, its consumption starts 1.000 years before Christ.