anteyesterday Share definition Flag The day before yesterday, phrased similarly to Romance languages, like Spanish or French. Elegant way of saying it... Wannabe Geek: Was The Big Bang Theory on yesterday? Language Nerd: No, it was on anteyesterday. anteyesterday by iUberGeek October 13, 2010 0 0 Get merch Get the anteyesterday mug. Buy Now — $32.95 See more merch