The cubit is an archaic unit of length based on the length of the forearm from the elbow to the tip of the middle finger. Cubits of various lengths were employed in many parts of the world in antiquity, during the Middle Ages and as recently as Early Modern Times. The term is still used in hedge laying, the length of the forearm being frequently used to determine the interval between stakes placed within the hedge.
Other units of measure based on the length of the forearm include some kinds of ell, the Indian Hasta, Khmer hat and Thai sok.
The earliest attested standard measure is from the Ancient Egypt and was called the royal cubit (meh niswt). Early evidence for the use of the royal cubit comes from the early dynastic period: on the Palermo stone, the flood level of the Nile river during the reign of the PharaohDjer is given as measuring 6 cubits and 1 palm. Use of the royal cubit is also known from Old Kingdom architecture, from at least as early as the construction of the Step Pyramid of Djoser in around 2,700 B.C.
In Ancient Egypt, cubit rods were used for the measurement of length. A number of these have survived: two are known from the tomb of Maya, the treasurer of Tutankhamun, in Saqqara; another was found in the tomb of Kha (TT8) in Thebes. Fourteen such rods, including one double cubit rod, were described and compared by Lepsius in 1865. These cubits range from 523 to 529 mm (20.6 to 20.8 in) in length, and are divided into seven palms; each palm is divided into four fingers and the fingers are further subdivided.
In 1916, during the last years of Ottoman Empire and in the middle of WWI, the German assyriologistEckhard Unger found a copper-alloy bar while excavating at Nippur. The bar dates from c. 2650 BCE and Unger claimed it was used as a measurement standard. This irregularly formed and irregularly marked graduated rule supposedly defined the Sumerian cubit as about 518.6 mm or 20.42 in.
Near Eastern or Biblical cubit
In biblical exegesis, the Near Eastern or Biblical cubit is usually estimated as approximately 450 mm or 18 in.
Other measurements based on the length of the forearm are the Indian Hasta and Thai sok. A traditional measure in South India commonly used by flower sellers is the mola , mulam which is equal to a cubit.
A cubit arm in heraldry may be dexter or sinister. It may be vested (with a sleeve) and may be shown in various positions, most commonly erect, but also fesswise (horizontal), bendwise (diagonal) and is often shown grasping objects. It is most often used erect as a crest, for example by the families of Poyntz of Iron Acton, Rolle of Stevenstone and Turton.
^Acta praehistorica et archaeologica Volumes 7–8. Berliner Gesellschaft für Anthropologie, Ethnologie und Urgeschichte; Ibero-Amerikanisches Institut (Berlin, Germany); Staatliche Museen Preussischer Kulturbesitz. Berlin: Bruno Hessling Verlag, 1976. p. 49.
^W. Gunther Plaut, Bernard J. Bamberger, William W. Hallo (eds.) (1981). The Torah. New York: Union of American Hebrew Congregations. ISBN 9780807400555. Footnote to Gen. 6:15: "figuring a cubit to be about 18 inches"