Definition of ruby

• n. - 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.
• n. - The color of a ruby; carmine red; a red tint.
• n. - That which has the color of the ruby, as red wine. Hence, a red blain or carbuncle.
• n. - See Agate, n., 2.
• n. - Any species of South American humming birds of the genus Clytolaema. The males have a ruby-colored throat or breast.
• a. - Ruby-colored; red; as, ruby lips.
• v. t. - To make red; to redden.