Dirham or dirhem or "Dirhm" (درهم) is a unit of currency in several Arab and North African nations, and formerly, the related unit of mass (the Ottoman dram) in the Ottoman Empire and Persian states. The name derives from the Greek currency drachma or didrachm (2 drachmae).
Currency units 
The currency units include:
- The Moroccan dirham
- The United Arab Emirates dirham
- 1/100 of the Iraqi Dinar
- 1/1000 of the Libyan dinar
- 1/100 of the Qatari riyal
- 1/10 of the Jordanian dinar
- The dirham, spelt 'diram,' is 1/100 of the Tajikistani somoni.
Unit of mass 
Known to the Romans as a drachm, the dirhem was a unit of weight used across North Africa, the Middle East, and Persia, with varying values.
Historically, the word "dirham" is derived from the name of a Greek coin, the Drachma (δραχμή); the Greek-speaking Byzantine Empire controlled the Levant and traded with Arabia, circulating the coin there in pre-Islamic times and afterward. It was this currency which was initially adopted as an Arab word; then near the end of the 7th century the coin became an Islamic currency bearing the name of the sovereign and a religious verse. The dirham was struck in many Mediterranean countries, including Al-Andalus (Moorish Spain) and the Byzantine Empire (miliaresion), and could be used as currency in Europe between the 10th and 12th centuries, notably in areas with Viking connections, such as Viking York and Dublin.
See also 
- based on an oka of 1.2828 kg; Diran Kélékian gives 3.21 g (Dictionnaire Turc-Français, Constantinople: Imprimerie Mihran, 1911) ; Γ. Μπαμπινιώτης gives 3.203 g (Λεξικό της Νέας Ελληνικής Γλώσσας, Athens, 1998)
- In addition to Islamic dirhams in ninth and tenth century English hoards, a counterfeit dirham was found at Coppergate, York, struck as if for Isma'il ibn Achmad (ruling at Samarkand, 903-07/8), of copper covered by a once-silvery wash of tin (illustrated in Richard Hall, Viking Age Archaeology, [series Shire Archaeology] 2010:17, fig. 7).