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• ruby
  ruby

  noun

  a red variety of corundum, used as a gem.
• Ruby
  Ruby

  noun

  a female given name.

ruby

¹ American  

[roo-bee] / ˈru bi /

noun

rubies plural

1. a red variety of corundum, used as a gem.

2. something made of this stone or one of its imitations, as a bearing in a watch.

3. a deep-red port wine.

4. deep red; carmine.

5. Digital Technology. Ruby, an open-source, high-level programming language that is purely object-oriented.

6. British Printing. a 5½-point type, nearly corresponding in size to American agate.

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adjective

1. ruby-colored.

   ruby lips.

2. containing or set or adorned with a ruby or rubies.

   a ruby necklace.

Ruby ² American  

[roo-bee] / ˈru bi /

noun

1. a female given name.

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ruby British  

/ ˈruːbɪ /

noun

1. a deep red transparent precious variety of corundum: occurs naturally in Myanmar and Sri Lanka but is also synthesized. It is used as a gemstone, in lasers, and for bearings and rollers in watchmaking. Formula: Al 2 O 3

2. 1. the deep-red colour of a ruby

   2. ( as adjective )

      ruby lips

3. 1. something resembling, made of, or containing a ruby

   2. ( as modifier )

      ruby necklace

4. (modifier) denoting a fortieth anniversary

   our ruby wedding

5. (formerly) a size of printer's type approximately equal to 5 1/ 2 point

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ruby Scientific  

/ ro̅o̅′bē /

1. A deep-red, translucent variety of the mineral corundum, containing small amounts of chromium and valued as a gem.

2. Compare sapphire

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Usage

What does ruby mean? A ruby is a transparent red gemstone. Rubies are one of the most well-known gemstones, along with diamonds, emeralds, and sapphires. They are classified as precious gems, meaning that they have a high commercial value. Rubies are quite rare and are considered one of the most valuable gems. Besides diamond, ruby is one of the hardest known natural substances. The ruby is the traditional birthstone for the month of July. It is associated with the zodiac signs Capricorn and Leo. The word ruby is also used to refer to a jewel-toned red color or describe things that are that color. The word is often used in the term ruby red, as in Look at that ruby red sports car! The word ruby is sometimes used to describe a 40-year anniversary, as in It’s my parents’ ruby anniversary this year—I can’t believe they’ve been married for 40 years!Ruby is also a given name, traditionally a female one. It’s also the name of a programming language. Example: The ring features a large ruby surrounded by diamonds. 

Other Word Forms

Derived Forms

• ruby-like
  adjective
• rubylike
  adjective

Inflected Forms

Nouns

• rubies
  plural

Etymology

Origin of ruby

First recorded in 1300–50; Middle English noun rubi from Old French, from Old Provençal robi(n) , from Medieval Latin rubīnus (lapis) “red (stone),” derivative of Latin ruber, rubeus red ¹

Explanation

A ruby is a gemstone that's usually a deep red. You can also describe things that are this same red color as ruby, like Dorothy's ruby slippers. Rubies are one of four types of precious stones — the others are diamonds, emeralds, and sapphires. A ruby can be any reddish shade from pink to dark red, and it's the official birthstone for people born in July. Less expensive rubies are often treated with high heat, which improves the color and clarity of the stone. Ruby comes from the Medieval Latin rubinus lapis, "red stone."

Example Sentences

In 1960, Theodore Maiman demonstrated the first working laser using a synthetic ruby rod and a photographer’s flash lamp.

From The Wall Street Journal • Apr. 24, 2026

They also gave the Queen a Tiffany & Co vintage 18-carat gold, diamond and ruby flower brooch.

From BBC • Oct. 2, 2025

About halfway through the show, Ross slipped into a pipe-and-drape dressing room at the rear of the stage then slipped back out wearing bedazzled ruby red; later, she changed into a shimmering gold look.

From Los Angeles Times • Jul. 26, 2025

It wore ruby strawberries and a drizzle of olive oil like jewelry.

From Salon • May 26, 2025

Its ruby eyes were windows to an interior furnace.

From "Ella Enchanted" by Gail Carson Levine

Related Words

• cardinal
• coral
• crimson
• flaming
• glowing
• maroon
• rose
• wine