1/60 dram; equals an avoirdupois grain or 64.799 milligrams WordNet 3.0 & Open English WordNet

A grain is a unit of measurement of mass, and in the troy weight, avoirdupois, and apothecaries' systems, equal to exactly 64.79891 milligrams. Wikipedia

A unit of mass equal to 64.79891 milligrams, 1⁄7,000 of an avoirdupois pound Wikipedia Disambiguation

Unit of mass Wikidata

A very small unit of weight, in England equal to 1⁄480 of an ounce troy, 0.0648 grams or, to be more exact, 64.79891 milligrams (0.002285714 avoirdupois ounce). A carat grain or pearl grain is 1⁄4 carat or 50 milligrams. The old French grain was 1⁄9216 livre or 53.11 milligrams, and in the mesures usuelles permitted from 1812 to 1839, with the livre redefined as 500 grams, it was 54.25 milligrams. Wiktionary

Unit of weight. Wiktionary (translation)