fils (pl. fulous). A small coin, an obolus or anything of similar shape; as the scale of a fish, the boss on a bridle or book
-English and Arabic Dictionary, Joseph Catafago, 1873
I had never considered that my use of the word fulous, which I always meant and understood to mean money as a collective noun, was actually the plural of the singular noun fils, which had a secondary meaning as any object shaped like a round coin, such as the decorative brass buttons attached to a horse bridle, or the iron bosses that covered the outside of doors along a public street, or fish scales.
A common response to a beggar is fulous ma feesh, there is no money, which might also be translated in a jokey bilingual way as money, not fish. Some Sudanese used an alternate word, qirsh (pl.quroush), meaning the coin of 1/100th the value of a guinea. In Sudan and Upper Egypt, the letter q is pronounced as a g, so guroush ma feesh is as commonly heard as fulous ma feesh.
Either way, the scale of a fish or one hundredth of a pound, a fils or a girsh was not much to fill one’s pocket, jaib (pl.juyoub), as in that belonging to my friend Abu Jaib, one of the wealthiest camel merchants in Sudan at one time, so wealthy that a camel drover I knew, Mas’ood abu Dood, told me that Abu Jaib would send a herd of female camels with a single bull and a few drovers to look after them for a year or two into the desert, telling them not to return until they had all foaled, and in that way he would double his fulous, which in the desert is as hard to come by as either a fish or a girsh.