old maid
n.— «The key to successful popcorn is the roughly 13 percent moisture inside each kernel, which makes it explode under heat. Lose the moisture and you’ve got duds, or what the popcorn industry calls Old Maids.» —“Tricks to making movie-style popcorn at home” by Victoria Brett Naples Daily News (Florida) Feb. 7, 2007. (source: Double-Tongued Dictionary)