dram

The dram (alternative British spelling drachm; apothecary symbol ʒ; abbreviatted dr) was originally both a coin and a weight in ancient Greece. 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. The unit of volume is more correctly called a fluid dram, fluid drachm, fluidram or fluidrachm (abbreviated fl dr, ƒ 3, or fʒ).
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.
In the avoirdupois system, the dram is the mass of ⁄256 pound or ⁄16 ounce. The dram weighs ⁄32 grains, or exactly 1.7718451953125 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 ⁄96 pounds apothecaries (lb ap), or ⁄8 ounces apothecaries (oz ap or ℥) (the pound apothecaries and ounce apothecaries are equal to the troy…