The dram (alternative British spelling drachm; apothecary symbol ʒ or ℨ; abbreviated dr) Earlier version first published in '' New English Dictionary'', 1897.National Institute of Standards and Technology (October 2011). Butcher, Tina; Cook, Steve; Crown, Linda et al. eds
"Appendix C – General Tables of Units of Measurement"
(PDF)
''Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices''
NIST Handbook. 44 (2012 ed.). Washington, D.C.: U.S. Department of Commerce, Technology Administration, National Institute of Standards and Technology.

ISSN An International Standard Serial Number (ISSN) is an eight-digit to uniquely identify a periodical publication (periodical), such as a magazine. The ISSN is especially helpful in distinguishing between serials with the same title. ISSNs a ...

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. Retrieved 1 July 2012. is a unit of

mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...

in the avoirdupois system, and both a unit of mass and a unit of volume in the apothecaries' system. It was originally both a

coin A coin is a small object, usually round and flat, used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order to facilitate trade. They are most often issued by ...

and a

weight In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition. Some sta ...

ancient Greece Ancient Greece () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically r ...

. The unit of volume is more correctly called a fluid dram, fluid drachm, fluidram or fluidrachm (abbreviated fl dr, ƒ 3, or fʒ).

Ancient unit of mass

*The Attic Greek drachma () was a weight of 6 obols, Greek mina, or about 4.37

gram The gram (originally gramme; SI unit symbol g) is a Physical unit, unit of mass in the International System of Units (SI) equal to one thousandth of a kilogram. Originally defined in 1795 as "the absolute Mass versus weight, weight of a volume ...

s. * The Roman drachma was a weight of Roman pounds, or about 3.41 grams. A coin weighing one drachma is known as a

stater The stater (; ) was an ancient coin used in various regions of Greece. The term is also used for similar coins, imitating Greek staters, minted elsewhere in ancient Europe. History The stater, as a Greek silver currency, first as ingots, and ...

, drachm, or drachma. The Ottoman dirhem () was based on the Sassanian drachm, which was itself based on the Roman dram/drachm.

British unit of mass

The British Weights and Measures Act 1878 introduced verification and consequent stamping of apothecary weights, making them officially recognized units of measurement. By 1900, Britain had enforced the distinction between the avoirdupois and apothecaries' versions by making the spelling different: *''dram'' now meant only avoirdupois drams, which were of an avoirdupois ounce. An ounce consisted of 437.5

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached husk, hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and ...

s, thus making the dram exactly 27.34375 grains. *''drachm'' now meant only apothecaries' drachms, which were of an apothecaries' ounce of 480 grains, or equal to 60 grains.

Modern unit of mass

In the avoirdupois system, the dram is the mass of pound or ounce. The dram weighs

grains A grain is a small, hard, dry fruit ( caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and le ...

, or exactly grams. In the apothecaries' system, which was widely used in the United States until the middle of the 20th century, the dram is the mass of pounds apothecaries (lb ap), or ounces apothecaries (oz ap or ℥) (the pound apothecaries and ounce apothecaries are equal to the

troy pound Troy weight is a system of Physical unit, units of mass that originated in the Kingdom of England in the 15th century and is primarily used in the precious metals industry. The troy weight units are the Grain (unit), grain, the pennyweight (24 ...

(lb t), and troy ounce (oz t), respectively). The dram apothecaries is equal to or , or exactly grams. "Dram" is also used as a measure of the powder charge in a shotgun shell, representing the equivalent of black powder in drams avoirdupois.

Unit of volume

The ''fluid dram'' (or ''fluid drachm'' in British spelling) is defined as fluid ounce, and is equal to: * in the U.S. customary system * in the British imperial system