Medical Definitions from the Annoyed Librarian
Librarian's Bottom is probably the most frequent physical deformity found in the profession of librarianship. The main symptom is having a bottom approximately as wide as your inseam is long. Extreme cases involve having a bottom as wide as you are tall. This unfortunate deformity strikes a disproportionately large number of librarians, often making them disproportionately large. No one is sure if librarians develop enormous bottoms because of their sedentary lifestyles and addiction to chocolate, or if instead people with enormous bottoms are somehow genetically predisposed to become librarians. Regardless, this plague affects an estimated 73% of all librarians.
Examples of Librarian's Bottom.