Corn

Corn in modern American parlance tends to mean specifically maize, a New World grain crop.

However in older usage, the word was used generically to mean any grain, and, indeed any object which came in roughly the size of a grain. One can easily find references to "corns of gunpowder" and so on. The process of "corning" (as in "corned beef") comes from packing the meat in "corns" of salt.