A unit of density for woolen yarn, used in the U.S. Yarn is described as n run if there are n 1600-yard hanks of the wool per pound. Actual yarn ranges from about 0.5 run to 8 run. The unit is also called the American run
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}