Barbacoa is a term that is mostly associated with Mexico and refers to an ancient technique of cooking meat in underground ovens.
There are numerous regional varieties, which usually differ in the type of meat or the cut, but the most common options include lamb, goat, or mutton—and animal heads are traditionally regarded as a favorite barbacoa specialty. Mexican barbacoa involved digging a hole in the ground, lining the bottom and the sides with rocks, and adding a layer of burning wood, which would then be covered with agave leaves.
The first mention of the word had Caribbean origins, where it was used for a contraption created with a framework of sticks. Another popular belief is that the word barbecue has its roots in the same word. Mexican barbacoa tradition is believed to have its origins in the ancient Mayan and Aztec cultures.
However, they did not use the name barbacoa. In some parts of Mexico, the words pibil, tatema, and birria are used to describe similar dishes cooked under the ground, but it is believed that they are all babacoa styles.