n (countable) 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.