Ruby
Middle English: from Old French rubi, from medieval Latin rubinus, from the base of Latin rubeus ‘red’.
wiktionary
From Middle English ruby, rube, from Old French rubi, from Latin rubeus(“red”).
From the British 5.5-point font Ruby, used for annotations in printed documents.
etymonline
ruby (n.)
valuable precious gem, in modern understanding a clear, rich-red variety of corundum, c. 1300, rubi, rubie (late 12c. as a surname), from Old French rubi (12c.), from Medieval Latin rubinus lapis "red stone" (source also of Italian rubino), from Latin rubeus "red," which is related to ruber (from PIE root *reudh- "red, ruddy").
As a name for a pure or somewhat crimson-red color, from 1570s. As an adjective from late 15c., "made from or with rubies;" c. 1500 as "of a ruby color." Modern French rubis is not explained; Klein suggests a plural mistaken for singular.
