Solidus.

Solidus. a Roman gold coin (see NUMISMATICS, Vol. VII. p. 552). The 'solidus aureus' was adopted by the Franks (at 87 to the Roman pound) till the time of Pepin, who suppressed it; but another solidus of silver, or 'solidus argenteus'—the $\backslash frac\{1\}\{20\}$th of the libra or pound—which had been used only as a money of account, was soon after made a coin. In later times this 'sol' or 'son,' like all other coins, underwent an infinity of variations in fineness and value (see LIVRE). On the introduction of the decimal system (1793) into France the son was abolished, and a piece of five centimes ($\backslash frac\{1\}\{20\}$th of a franc) substituted; but the name continued in common use, and the old sons were retained in circulation. The solidus also appears in the soldo of some parts of Italy, which was substantially the same as the son. A trace survives in the s. of £ s. d.