A unit of time equal to exactly 365.2425 days, the average length of a year in the Gregorian calendar currently used throughout the world. See: Year [2]
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}