Solidus, a Roman gold coin adopted by the Franks, and first coined by them in gold, but subsequently in silver, when it was equivalent to one-twentieth of the libra, or pound; as the "sol" or "sou" it depreciated greatly in value; was minted in copper, and on the introduction of the decimal system its place was taken by a five-centime piece; the "soldo" in Italy, and the Solidus L.S.D. owe their origin to this coin.