The fals (plural fulus) was a medieval copper coin first produced by the Umayyad caliphate (661-750) beginning in the late 7th century. The name is a corruption of follis, a Roman and later Byzantine copper coin. The fals usually featured ornate Arabic script on both sides. Various copper fals were produced until the 19th century. Their weight varied, from one gram to ten grams or more. The term is still used in modern spoken Arabic for money, but pronounced 'fils'.
- Stephen Album, Checklist of Islamic Coins, Santa Rosa, CA, 2011, third edition, p. 7