The exact domestication point for maize is unknown, but it is estimated that the crop is at least 5,000 years old. The plant was originally domesticated in Mesoamerica, and appears to be related to species of wild grass which still exist in Central American today. People in many English speaking nations know maize as corn. Originally, the term "corn" could refer to any type of grain. When maize was brought back to Europe, it was called "Indian corn," a reference to the source of the plant. The term was shortened to "corn" as maize became ubiquitous in many gardens. In Africa, it is known as mealies.