headache bar n. a tube or beam suspended horizontally so as to block or bang against vehicles that are too tall for passage; a vehicle’s roll bar or headache rack; any horizontal tube or beam with which a person could collide. Editorial Note: The Historical Dictionary of American Slang dates the near-synonym headache post to 1887. (source: Double-Tongued Dictionary)
Further reading
Joe from Fort Lauderdale, Florida, asks about pony, the term he and his fellow maritime academy students used to mean “a practice test” or “a copy of a previous test” to help them crib for an exam. Among 19th-century British students, the slang term...
You know the expression fly in the ointment: It’s that glaring typo on an impressive resume or that first scratch on a brand-new car—the one little flaw that spoils it all. This phrase goes all the way back to the biblical Book of Ecclesiastes! And...