horse blanket n. a large, complex, or comprehensive report or chart. Etymological Note: Probably derives from a size comparison of sheets of chart paper to actual horse blankets. (source: Double-Tongued Dictionary)
Further reading
Mark in Bismarck, North Dakota, spent years as a sailor, and wonders about the term sea painter, meaning “a rope attached to a lifeboat.” Why painter? The word may derive from Middle French pendeur meaning “a kind of rope that...
A resident of Michigan’s scenic Beaver Island shares the term, boodling, which the locals use to denote the social activity of leisurely wandering the island, often with cold fermented beverages. There have been various proposed etymologies...