Dram (unit)
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The dram (archaic spelling drachm; apothecary symbol ℨ) was historically both a coin and a weight. Currently it is both a small mass in the Apothecaries' system of weights and a small unit of volume. This unit is called more correctly fluid dram or in contraction also fluidram.
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[edit] Ancient unit of mass
- The Greek drachm was a weight of 1⁄100 Greek mine, which is about 4.37 grams.
- The Roman drachm was a weight of 1⁄96 Roman pounds, which is about 3.41 grams.
Greek and Roman drachm were related by the approximate ratio 25 : 32.
The Ottoman dirhem is based on the Sassanian drachm which was itself based on the Roman dram/drachm. Modern Armenian drams, the currency of the Republic of Armenia, share this origin.
[edit] Modern unit of mass
The dram is the mass of 1⁄256 pound avoirdupois or 1⁄16 ounce. So the dram weighs 875⁄32 grains or about 1.771845 grams.
The dram (symbol: ʒ) was also the mass of 1⁄96 pound (℔) or 1⁄8 ounce (℥) in the apothecaries' system that survived until the middle of the 20th century in English-speaking countries. It was equal to 3 scruples (℈) or 60 grains (G). Thus, it was equal to 3.888 grams (in the SI).
[edit] Unit of volume
The fluid dram is defined as 1⁄8 of a fluid ounce, which means it is exactly equal to
- 3.696 691 195 312 5 mL in the United States and
- 3.551 632 812 500 0 mL in the Commonwealth and Ireland.
In the United Kingdom, a teaspoon was formerly defined as 1 fluid dram.
Dram is also used informally to mean a small amount of liquid, especially Scotch whisky.
[edit] See also
