Spat 1 : A unit of solid angle measure equal to the sphere, that is, 4(pi) steradians (see below). This usage comes from the Latin word spatium, space, since a solid angle of 1 spat covers all of space surrounding the vertex of the angle
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}