CrithCrith\ (kr?th), n. [Gr. ??? a barleycorn, a small weight.] (Chem.) The unit for estimating the weight of a?riform substances; -- the weight of a liter of hydrogen at 0? centigrade, and with a tension of 76 centimeters of mercury. It is 0.0896 of a gram, or 1.38274 grains.