apothecaries' system

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apothecaries' system

 
a system used for measuring and weighing drugs and solutions, brought to the United States from England during the colonial period; it has now been replaced by the metric system. Its units are the grain, scruple, dram, ounce, and pound. Fractions are used to designate portions of a unit of measure: e.g., one-fourth grain is written gr. 1/4. The fraction 1/2 is written ss. There are two symbols in this system which are sometimes confused and always must be written clearly, those for drams and ounces. Lower case Roman numerals are used after the symbols: ʒiss reads drams one and one-half; ℥iii reads ounces three. See also Table of Weights and Measures in the Appendix.