1a precious stone consisting of corundum in colour varieties varying from deep crimson or purple to pale rose:a necklace of rubies [as modifier]:a ruby eternity ring
[mass noun] an intense purplish-red colour: [as modifier]:the rich ruby liquid [in combination]:this wine has a youthful ruby-red colour
2 [mass noun] Printing an old type size equal to 5 1/ 2 points.
