Masa, also called masa harina when it is dried and powdered, is a dough made from nixtamalized corn (maize). It is a critical ingredient for many Latin American dishes, including tortillas, tamales, pupusas, and chochoyotes, and beverages such as atole and champurrado.
It is not the same as corn meal, which has not been nixtamalized, and therefore will not hold water like masa.