Dram (unit)

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The dram (archaic spelling drachm) 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.

[edit] Drachm (ancient 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 Roman dram/drachm.

[edit] Dram (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] Dram (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

• Avoirdupois
• Imperial unit
• U.S. customary units
• Apothecaries' systemde:Dram (Einheit)

es:Dracma (unidad de masa) fr:Drachme (unité) ja:ドラム (単位)