The smoot is a unit of length resulting from a MIT fraternity prank. In October of 1958, Oliver R. Smoot, pledging Lambda Chi Alpha fraternity, repeatedly laid down on the bridge between Boston and Cambridge, Massachusetts (the “Harvard Bridge”). His fraternity brothers used his height to measure the length of the bridge. At the time Smoot was 5 feet 7 inches (1.70 m) and they measured the bridge’s length at 364.4 smoots (2,035 ft; 620.1 m) with a +/- indicating some uncertainty in the measurement.
Graffiti on the bridge still divides it up into Smoot-based sections and in 2011 the word ‘smoot’ was added to the American Heritage Dictionary, defined as “a unit of measurement equal to five feet, seven inches.” A 50th-anniversary plaque at the end of the bridge commemorates the prank. Oliver R. Smoot went on, among other accomplishments, to become Chairman of the American National Standards Institute.