The Useless Digest A Free Weekly dose of Facts, Quotes, History and more - direct to your inbox. In Britain corn generally refers to wheat. However, in the US, the word corn refers to maize. Popping corn is just one of the many varieties of maize grown commercially. The bulk of tissue within a grain of corn is called the endosperm.
Endosperm is specialized storage tissue providing nutrients for the embryo when the seed germinates.
It is also a source of carbohydrates for humans. In popcorn, the outer part of the endosperm is hard but the center is soft.