1.  ruby(n = noun.possession) - a transparent piece of ruby that has been cut and polished and is valued as a precious gem;
is a kind of gem, jewel, precious stone

2.  ruby(n = noun.substance) - a transparent deep red variety of corundum; used as a gemstone and in lasers;
is a kind of corundom, corundum, transparent gem

3.  ruby(n = noun.attribute) crimson, deep red - a deep and vivid red color;
is a kind of red, redness
Derived form verb rubify₁

   ruby(s = adj.all) blood-red, carmine, cerise, cherry, cherry-red, crimson, red, reddish, ruby-red, ruddy, scarlet - of a color at the end of the color spectrum (next to orange); resembling the color of blood or cherries or tomatoes or rubies;

1.  A precious stone of a carmine red color, sometimes verging to violet, or intermediate between carmine and hyacinth red. It is a red crystallized variety of corundum. [1913 Webster]
" Besides the true or Oriental ruby above defined, there are the balas ruby, or ruby spinel, a red variety of spinel, and the rock ruby, a red variety of garnet." [1913 Webster]
"Of rubies, sapphires, and pearles white." [1913 Webster]

2.  The color of a ruby; carmine red; a red tint. [1913 Webster]
"The natural ruby of your cheeks." [1913 Webster]

3.  That which has the color of the ruby, as red wine. Hence, a red blain or carbuncle. [1913 Webster]

4.  See Agate, n., 2. [1913 Webster]

5.  Any species of South American humming birds of the genus Clytolæma. The males have a ruby-colored throat or breast. [1913 Webster]

   Ruby-colored; red; as, ruby lips. [1913 Webster]

   To make red; to redden. Pope. [1913 Webster]

ruby, n., adj., & v.
--n. (pl. -ies)
1 a rare precious stone consisting of corundum with a colour varying from deep crimson or purple to pale rose.
2 a glowing purple-tinged red colour.
--adj. of this colour.
--v.tr. (-ies, -ied) dye or tinge ruby-colour.

Idiom:
ruby glass glass coloured with oxides of copper, iron, lead, tin, etc. ruby-tail a wasp, Chrysis ignita, with a ruby-coloured hinder part. ruby wedding the fortieth anniversary of a wedding.

Etymology:
ME f. OF rubi f. med.L rubinus (lapis) red (stone), rel. to L rubeus red

N  goodness, excellence, merit, virtue, value, worth, price, super-excellence, supereminence, superiority, perfection, coup de maitre, masterpiece, chef d'ouvre, prime, flower, cream, elite, pick, A, nonesuch, nonpareil, creme de la creme, flower of the flock, cock of the roost, salt of the earth, champion, prodigy, tidbit, gem, gem of the first water, bijou, precious stone, jewel, pearl, diamond, ruby, brilliant, treasure, good thing, rara avis, one in a thousand, beneficence, good man, harmless, hurtless, unobnoxious, innocuous, innocent, inoffensive, beneficial, valuable, of value, serviceable, advantageous, edifying, profitable, salutary, favorable, propitious fair, good, good as gold, excellent, better, superior, above par, nice, fine, genuine, best, choice, select, picked, elect, recherche, rare, priceless, unparagoned, unparalleled, superlatively, good, bully, crackajack, giltedged, superfine, superexcellent, of the first water, first-rate, first-class, high- wrought, exquisite, very best, crack, prime, tiptop, capital, cardinal, standard, inimitable, admirable, estimable, praiseworthy, pleasing, couleur de rose, precious, of great price, costly, worth its weight in gold, worth a Jew's eye, priceless, invaluable, inestimable, precious as the apple of the eye, tolerable, up to the mark, unexceptionable, unobjectionable, satisfactory, tidy, in good condition, in fair condition, fresh, sound, beneficially, well, Jewels five words long, long may such goodness live!, the luxury of doing good.

N  jewel, jewelry, jewellery, bijoutry, bijou, bijouterie, trinket, fine jewelry, costume jewelry, junk jewelry, gem, gemstone, precious stone, necklace, bracelet, anklet, earring, locket, pendant, charm bracelet, ring, pinky ring, carcanet, chain, chatelaine, broach, pin, lapel pin, torque, diamond, brilliant, rock, beryl, emerald, chalcedony, agate, heliotrope, girasol, girasole, onyx, plasma, sard, sardonyx, garnet, lapis lazuli, opal, peridot, tourmaline, chrysolite, sapphire, ruby, synthetic ruby, spinel, spinelle, balais, oriental, oriental topaz, turquois, turquoise, zircon, cubic zirconia, jacinth, hyacinth, carbuncle, amethyst, alexandrite, cat's eye, bloodstone, hematite, jasper, moonstone, sunstone, pearl, cultured pearl, fresh-water pearl, mother of pearl, coral, jeweler, gemologist, minerologist, lapidary, lapidarian, gemology, gemmology, minerology, bejeweled, diamond, (gemstones), gemological.

N  redness, red, scarlet, vermilion, carmine, crimson, pink, lake, maroon, carnation, couleur de rose, rose du Barry, magenta, damask, purple, flesh color, flesh tint, color, fresh color, high color, warmth, gules, ruby, carbuncle, rose, rust, iron mold, cinnabar, cochineal, fuchsine, ruddle, madder, Indian red, light red, Venetian red, red ink, annotto, annatto, realgar, minium, red lead, redness, rubescence, rubicundity, rubification, erubescence, blush, red, reddish, rufous, ruddy, florid, incarnadine, sanguine, rosy, roseate, blowzy, blowed, burnt, rubicund, rubiform, lurid, stammell blood red, russet buff, murrey, carroty, sorrel, lateritious, rubineous, rubricate, rubricose, rufulous, rose-colored, ruby-colored, cherry-colored, claret-colored, flame- colored, flesh-colored, peach-colored, salmon-colored, brick-colored, brick-colored, dust-colored, blushing, erubescent, reddened, red as fire, red as blood, red as scarlet, red as a turkey cock, red as a lobster, warm, hot, foxy.

balas ruby, ruby spinel, ruby wood, spinel ruby