Drachm

The dram (alternative British spelling drachm; apothecary symbol ʒ; abbreviated dr)^{[1][2]:C-6–C-7[3]} was originally both a coin and a weight in ancient Greece.^[4] It refers to a unit of mass in the avoirdupois system, and both a unit of mass and a unit of volume in the apothecaries' system.^[2] The unit of volume is more correctly called a fluid dram, fluid drachm, fluidram or fluidrachm (abbreviated fl dr, ƒ 3, or fʒ).^{[1][2]:C-17[3][5][6][7]}

Ancient unit of mass

• The Attic Greek drachma was a weight of 6 obols, ¹⁄₁₀₀ Greek mina, or about 4.37 grams.^[8]
• The Roman drachma was a weight of ¹⁄₉₆ Roman pounds, or about 3.41 grams.^[9][10]

The Ottoman dirhem was 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.

Modern unit of mass

In the avoirdupois system, the dram is the mass of ¹⁄₂₅₆ pound or ¹⁄₁₆ ounce.^[2]:C-6 The dram weighs ⁸⁷⁵⁄₃₂ grains,^[2]:C-6 or exactly 1.771845195-9-7-83 grams.^[2]:C-14

In the apothecaries' system, which was widely used in the United States until the middle of the 20th century,^[11] the dram is the mass of ¹⁄₉₆ pounds apothecaries (lb ap), or ¹⁄₈ ounces apothecaries (oz ap or ℥)^[2]:C-7 (the pound apothecaries and ounce apothecaries are equal to the troy pound (lb t), and troy ounce (oz t), respectively).^{[2]:C-6–C-7} The dram apothecaries is equal to 3 scruples (s ap or ℈) or 60 grains (gr),^[2]:C-7 or exactly 3.8879346 grams.^[2]:C-14

"Dram" is also used as a measure of the powder charge in a shotgun shell, representing the equivalent of black powder in drams avoirdupois.^[12]

Unit of volume

The fluid dram is defined as ¹⁄₈ of a fluid ounce,^[2]:C-5,C-7 and is exactly equal to:

• 3.696697109-913 ml in US customary units [3785.41784 ÷ 1024]^[2]:C-5,C-12
• 3.5516328129 ml in British Imperial units [4546.09 ÷ (160 × 8)]^[2]:C-7[13]

A teaspoonful has been considered equal to one fluid dram for medical prescriptions.^[14] However, by 1876 the teaspoon had grown considerably larger than it was previously, measuring 80–85 minims.^[15] As there are 60 minims in a fluid dram,^[2]:C-5,C-7 using this equivalent for the dosage of medicine was no longer suitable.^[15] Today's teaspoon is equivalent to approximately 1 ¹⁄₃ US fluid drams,^[2]:C-18 or 80 US minims.^[2]:C-5

Dram is also used informally to mean a small amount of spirituous liquor, especially Scotch whisky.^[4]

See also

• Avoirdupois
• Apothecaries' system
• Imperial unit
• U.S. customary units

References

External links

Look up dram in , the free dictionary.

• . NIST Handbook 44 (2012 ed.).
• Image of Ancient Greek silver drachm with flying Pegasus, Acarnania, Leucas, c. 470–450 BCE