The dram (alternative British spelling drachm; apothecary symbol ʒ or ℨ; abbreviated dr) Earlier version first published in ''

New English Dictionary The ''Oxford English Dictionary'' (''OED'') is the first and foundational historical dictionary of the English language, published by Oxford University Press (OUP). It traces the historical development of the English language, providing a com ...

'', 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 serial number used to uniquely identify a serial publication, such as a magazine. The ISSN is especially helpful in distinguishing between serials with the same title. ISSNs ...

br>0271-4027

OCLC OCLC, Inc., doing business as OCLC, See also: is an American nonprofit cooperative organization "that provides shared technology services, original research, and community programs for its membership and the library community at large". It was ...

. Retrieved 1 July 2012. is a unit of

mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementar ...

in the

avoirdupois The avoirdupois system (; abbreviated avdp.) is a measurement system of weights that uses pounds and ounces as units. It was first commonly used in the 13th century AD and was updated in 1959. In 1959, by international agreement, the definiti ...

system, and both a unit of mass and a unit of volume in the

apothecaries' system The apothecaries' system, or apothecaries' weights and measures, is a historical system of mass and volume units that were used by physicians and apothecaries for medical prescriptions and also sometimes by scientists."Medicinal-Gewicht, Apotheke ...

. It was originally both a

coin A coin is a small, flat (usually depending on the country or value), round piece of metal or plastic 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 t ...

and a

weight In science and engineering, the weight of an object is the force acting on the object due to gravity. Some standard textbooks define weight as a Euclidean vector, vector quantity, the gravitational force acting on the object. Others define weigh ...

ancient Greece Ancient Greece ( el, Ἑλλάς, Hellás) was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity ( AD 600), that comprised a loose collection of cult ...

. 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 The drachma ( el, wikt:δραχμή, δραχμή , ; pl. ''drachmae'' or ''drachmas'') was the currency used in Greece during several periods in its history: # An Ancient Greece, ancient Greek currency unit issued by many Greek city states du ...

() 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 one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure wate ...

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 (; grc, , , statḗr, weight) was an ancient coin used in various regions of Ancient Greece, Greece. The term is also used for similar coins, imitating Greek staters, minted elsewhere in ancient Europe. History The stater, as a Gr ...

, drachm, or drachma. The Ottoman

dirhem The dirham, dirhem or dirhm ( ar, درهم) is a silver unit of currency historically and currently used by several Arab and Arab influenced states. The term has also been used as a related unit of mass. Unit of mass The dirham was a un ...

( ota, درهم) was based on the

Sassanian The Sasanian () or Sassanid Empire, officially known as the Empire of Iranians (, ) and also referred to by historians as the Neo-Persian Empire, was the last Iranian empire before the early Muslim conquests of the 7th-8th centuries AD. Named ...

drachm, which was itself based on the Roman dram/drachm.

British unit of mass

The British

Weights and Measures Act A weights and measures act is a kind of legislative act found in many jurisdictions establishing technical standards for weights and measures. Notable acts of this type include: * Various Weights and Measures Acts (UK) or the various legislative ...

of 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 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 legum ...

s, thus making the dram approximately 27.34 grains. *''drachm'' now meant only apothecaries' drachms, which were of an apothecaries' ounce of 480 grains, thus equal to 60 grains.

Modern unit of mass

In the

system, the dram is the mass of pound or

ounce The ounce () is any of several different units of mass, weight or volume and is derived almost unchanged from the , an Ancient Roman units of measurement, Ancient Roman unit of measurement. The #International avoirdupois ounce, avoirdupois 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 legume ...

, or exactly grams. In the

, 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 units of mass that originated in 15th-century England, and is primarily used in the precious metals industry. The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 pennyweights), and the ...

(lb t), and

troy ounce Troy weight is a system of units of mass that originated in 15th-century England, and is primarily used in the precious metals industry. The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 pennyweights), and the ...

(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 of a

fluid ounce A fluid ounce (abbreviated fl oz, fl. oz. or oz. fl., old forms ℥, fl ℥, f℥, ƒ ℥) is a unit of volume (also called ''capacity'') typically used for measuring liquids. The British Imperial, the United States customary, and the United St ...

, and is exactly equal to: * in the U.S. customary system * in the

British Imperial system The imperial system of units, imperial system or imperial units (also known as British Imperial or Exchequer Standards of 1826) is the system of units first defined in the British Weights and Measures Act 1824 and continued to be developed thro ...