solidus

Etymology

From Middle English solidus, from classical Latin solidus (“solid”), see below. Doublet of sol, sold, soldo, solid, sou, and xu. In numismatic and weight senses, via medieval Latin solidus (“various coins”), from Late Latin solidus (“a gold coin of the Roman Empire”). In chemical sense, via German Solidus, coined by H.W.B. Roozeboom in his 1899 Zeitschrift für Physikalische Chemie, Stöchiometrie, und Verwandtschaftslehre (XXX, page 387). In typography, from the shilling mark originally being an abbreviation (a long s ⟨ſ⟩), of Medieval Latin solidus meaning shilling.