Definition of: ruby

(r′bē) noun plural ·bies
1. A red variety of corundum including specimens of great value as gemstones.
2. An ornament or a watchmaker's jewel fashioned of ruby.
3. A rich red color like that of a ruby.
4. Something like a ruby in color, as red wine or a carbuncle.
5. In England, a size of type (5½ points): equivalent to the American agate.
—adjective Pertaining to or like a ruby; being of a rich crimson: ruby lips.
—v.t. ·bied, ·by·ing To redden; tint with the color of a ruby. [<OF rubi <L rubeus red]