What is Gules?

Legal Definition
In heraldry, gules (/ˈɡjuːlz/) is the tincture with the colour red, and belongs to the class of dark tinctures called "colours". In engraving, it is sometimes depicted as a region of vertical lines or else marked with gu. as an abbreviation.

In Polish heraldry, gules is the most common tincture of the field. Through the sixteenth century, nearly half of all noble coats of arms in Poland had a field gules with one or more argent charges on them.

The original coat of arms of the d'Albret family was plain gules.

Sometimes, the different tinctures are said to be connected with special meanings or virtues, and represent certain elements and precious stones. Even if this is an idea mostly disregarded by serious heraldists throughout the centuries, it may be of anecdotal interest to see what they are, since people often ask for this information. Many sources give different meanings, but the gules tincture is often said to represent the following:

  • of jewels, the ruby;
  • of heavenly bodies, Mars.
-- Wikipedia
Legal Definition
The heraldic name of the color Usually called "red." The word is derived from the Arabic word "gule," a rose, and was probably introduced by the Crusaders. -Gules is denoted in engravings by numerous perpendicular lines. Heralds who blazoned by planets and jewels called it "Mars," and "ruby." Wharton.
-- Black's Law Dictionary