A metate (or mealing stone) is a mortar, a ground stone tool used for processing grain and seeds. In traditional Mesoamerican culture, metates were typically used by women who would grind calcified maize and other organic materials during food preparation (e.g., making tortillas). Similar artifacts are found all over the world, including China.

While varying in specific morphology, metates adhere to a common shape. They typically consist of large stones with a smooth depression or bowl worn into the upper surface. The bowl is formed by the continual and long-term grinding of materials using a smooth hand-held stone (known as a mano). This action consists of a horizontal grinding motion that differs from the vertical crushing motion used in a mortar and pestle. The depth of the bowl varies, though they are typically not deeper than those of a mortar; deeper metate bowls indicate either a longer period of use or greater degree of activity (i.e., economic specialization).

Another type of metate, called a grinding slab, may also be found among boulder or exposed bedrock outcroppings. The upper face of the stone is used for grinding materials, such as acorns that results in the smoothing of the stone's face and the creation of pocked dimples (see image).