Scruple

anciently any very small measure. The scruple was used by the Greeks to designate the 24th part of an uncia of land, the 24th part of an hour, and the 24th part of an ounce. The term had the same use among the Latins. Among English-speaking people it refers to weight only, the scruple being a third of a dram or the 24th part of an ounce apothecaries' weight, equivalent to 20 grains Troy. The term is not to be confused with scruple, meaning hesitation or uneasiness, save that both words are related to scrupulus, a Latin term meaning a sharp stone, a grain of sand, and doubt.