Karo - French: Carreau; English: diamonds; or ( four-color sheet ) - is one of the four match colors in the French game of card.
In the German pages, it corresponds clamps.
In older game descriptions Karo is also often referred to as the cornerstone. In Switzerland, the color is still called " Harrow " ( corner). The term Karo came in the 18th century on the French carreau in the German language and comes from Latin QUADRUM " rectangle, square " back.
The symbol ♦ is already included in the CP437 and thus also in the WGL4. In Unicode, a black and a white ♦ ♢ Karo is defined: