A corncob is the hard, woody center of an ear of corn that holds all the kernels. When you eat corn on the cob at a summer barbecue, you're biting the yellow kernels off that central cylinder. After you've eaten all the corn, what's left in your hand is the corncob itself: rough, cylindrical, and covered with little indentations where each kernel was attached.

Before modern materials became common, people found clever uses for dried corncobs. Farmers used them as fuel for fires, as stoppers for bottles, or ground them up for animal bedding. In Laura Ingalls Wilder's Little House books, the family uses a corncob to plug a syrup jug.

The term corncob also appears in the phrase “rough as a corncob,” describing something or someone coarse and unrefined. If you've ever held a dried corncob, you know exactly why: the surface feels scratchy and bumpy, nothing like the smooth kernels that once covered it.