Cardinal

The word "cardinal" comes from the Latin cardo for "hinge" and usually refers to things of fundamental importance, as in cardinal rule or cardinal sins.

1. In mathematics, cardinal is short for cardinal number.
2. In Catholicism, a cardinal is a prince of the Church; cardinals are appointed by the Pope and collectively elect the next Pope if they are under the age of eighty at the time of the election. See Cardinal (Catholicism).
3. In biology, a cardinal is the songbird Cardinalis cardinalis. They are red, similar to the dress of cardinals in the catholic church, hence the name. Cardinals belong to the finch family. (Pictured at right)
4. Cardinal is a bright red color like the color of the robe of a cardinal.
5. In sports, the Cardinals are a baseball team in St. Louis, Missouri (see St. Louis Cardinals) and an American football team in Arizona (see Arizona Cardinals). Also, the Cardinal (singular, referring to the color) is the mascot for teams from Stanford University, California.