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The solidus was the name of a gold coin minted by the ancient Romans. You/he/she was introduced with the monetary reform of Costantino I in 309/310 and used in the whole Byzantine empire up to the X century. The coin replaced the golden one as principal gold coin of the empire Romano.
The Solid name had been used in precedence by Diocleziano (284-305) for a gold coin from him introduced, that was different from the Solid of Costantino. The coin was sent forth to a theoretical value of 1/72 of Roman pound (around 4,5 grams). The Solid were more breadths and thin of the Golden ones, to exception of some issues of the Byzantine empire, more similar to the golden one. The weight and the fineness of the Solid remained constant relativmente for the whole period of its production, with few exceptions. You/they were also produced some fractions of the Solid, you call semisse (Solid mean) and tremisse (a bystander of Solid).
The Dinar was coin golden base of the Arabic monetary system in medieval epoch. Its weight was of 4,25 gs ca of pure gold. It derives the name from the Latin denarius (implied aureus); coined to imitation of the Byzantine solidus, it broadly circulated in western Europe.
Variations of the Solid term were been you use for different European currencies.
In France, sol was the name from a coin from 12 moneys, a twentieth of the pound tornese. After the introduction of the decimalization in France, the sou became the name of the coin from five centimes, a twentieth of the French Franco.
Up to the introduction of the decimalization in the United Kingdom, happened in 1971, the abbreviation s., from Solid, you/he/she was used for representing the shilling, that a twentieth of Lira Pound was worth.