solidus

plural solidi · plural soliduses

1. Various medieval and early modern coins or units of account
   1. historicalA Roman ~23k gold coin introduced by Diocletian in AD 301 and called by that name, but reissued at a slightly lower weight by Constantine I.
   2. historicalIts successor Byzantine coins, from the eleventh century onward of progressively debased weight and purity.

      Synonyms: nomisma, hyperpyron, bezant

   3. historicalobsoleteSynonym of sol or sou: a Carolingian unit of account equivalent to a solidus of silver.

      Synonyms: sol, sou

   4. historicalobsoleteSynonym of soldo: the silver coins of various Italian states.

      Synonyms: soldo

   5. historicalobsoleteSynonym of shilling: an English unit of account and, following the Tudor dynasty, silver coin.

      Synonyms: shilling

2. historicalThe weight of the Roman gold coin, 1/60 of a Roman pound under Diocletian or 1/72 lb. (about 4.5 grams) after Constantine.
3. historicalA medieval French weight, 1/20 of the Carolingian pound.
4. mediaSynonym of slash ⟨/⟩, originally (UK) in its use as the shilling mark and now its formal designation by the ISO and Unicode.

   Synonyms: slash, originally

5. mediaThe formal name of the oblique strikethrough overlay (as in A̷ and B̸) in Unicode.
6. mediaThe division line between the numerator and the denominator of a fraction, whether horizontal or oblique.
7. chemistryThe line in a phase diagram marking the temperatures and pressures below which a given substance is a stable solid.