Euphemism for a need to use a toilet. The term dates from the mid-1700s. It appeared in Tailor and Cutter (Oct. 14, 1852): “The calls of nature are permitted and Clerical Staff may use the garden below the second gate.” Much more recently, a New York Times restaurant review by Frank Bruni told patrons, “Be sure to head downstairs to the bathrooms, even if nature doesn’t call” and goes on to describe their attractive appearance (Jan. 26, 2005). A similar euphemism, used mostly by women, is to powder one’s nose. Another euphemistic cliché for a restroom is little boys’ room, used by men no matter what their age.