The origin of the term "old maids" for unpopped kernels of popcorn is unknown, but it has been in use for more than 100 years. For example, the term appeared in the 1947 edition of the "New England Cooking" cookbook by Ella S. Bowles and Dorothy S. Towle and in the May 21, 1949 edition of the Saturday Evening Post.
Unpopped kernels of popcorn have other colorful nicknames too. These include "duds," "flopcorn," "old bachelors," "pooped corn" and "widows."
"Old maids" can be used again as long as the water that has evaporated from the kernels is replaced. Placing the kernels in a jar with a small amount of water and shaking the jar until the water is absorbed can give "old maids" new life.