The smoot is a unit of length equal to 1.7018 meters. It is defined as the height of one Oliver R. Smoot, Jr., who as a freshman fraternity pledge to the Lambda Chi Alpha fraternity of the Massachusetts Institute of Technology (MIT) in October, 1958, repeatedly lay down on the Harvard Bridge between Boston, Massachusetts and Cambridge, Massachusetts and was used by his fraternity brothers to measure the length of the bridge at precisely 364.4 smoots, plus or minus one ear.

To measure the bridge, the 5'7" Smoot was repeatedly made to lie down while the other members of the fraternity marked off each smoot with chalk. When Smoot eventually became too exhausted to continue, he was carried bodily to the last few positions by the others.

People walking on the bridge today can still see the painted markings indicating how many smoots they are away from the start of the bridge on the Boston side of Charles River. The smoot markings generally appear at 10-smoot intervals, with some special exceptions, such as the 69 smoot mark. At the 182.2-smoot mark, the words "halfway to hell" appear, with an arrow pointing toward the MIT campus. Repainting the markings each year is one of the responsibilities of each new pledge class of Lambda Chi Alpha.

The smoot markings have become widely accepted and even celebrated by the citizens of the greater Boston area. Cambridge police are said to use the smoot markings in reporting the location of accidents on the bridge, and following a 1980 renovation of the bridge, not only was Lambda Chi Alpha asked to repaint the markings, but the construction workers even went ahead and scored the sidewalk every 5 feet 7 inches, rather than the normal 6 feet.

Today the smoot lives on as a humorous measurement used jocularly by those in the know, and can be found as an easter egg optional unit of measure in programs like Google Earth.

And what became of the now legendary Oliver R. Smoot, Jr.? Well, after having his body form the basis of a standardized measure, what else could he do in life but eventually go on to become the chairman of the American National Standards Institute (ANSI) and later president of the International Organization for Standardization (ISO)?