Popcorn, also known as popping corn, is a type of corn (maize, Zea mays var. everta) that expands from the kernel and puffs up when heated. Popcorn is able to pop because, like amaranth grain, sorghum, quinoa, and millet, its kernels have a hard moisture-sealed hull and a dense starchy interior. When heated, pressure builds within the kernel, and a small explosion (or "pop") is the end result. Some strains of corn are now cultivated specifically as popping corns.
There are various techniques for popping corn. Along with prepackaged popcorn, which is generally intended to be prepared in a microwave oven, there are small home appliances for popping corn. These methods require the use of minimally processed popping corn.