A tomatillo is a small green Mexican fruit that is part of the tomato family. It is a basic ingredient in Mexican cooking. Tomatillos are small and grow inside of husks. They can range in size from about an inch in diameter to the size of apricots. Tomatillos are covered by a papery husk that looks something like the onion husk. The husk should be removed, since it is not edible.
The botanical name of the tomatillo is Physalis philadelphica.
Also Known As: A tomatillo is also called tomate verde in Mexico, which means, "green tomato."
When you order Mexican food that has green sauce, like Enchiladas Verde, or Salsa Verde, that sauce was made with tomatillos.