Note:  Do not rely on this information. It is very old.

Cardinal

Cardinal, the name given to the highest dignitaries of the Roman Church next after the Pope, who is chosen by the Sacred College of Cardinals. The name is derived from the Latin cardo (a hinge), but there is a difference of opinion as to how it came to be applied to them, the general idea being that they were originally those who were "hinged in" or established in the churches of Rome, either as deacons aiding the Pope, or priests of the city churches, or bishops in the Roman diocese. Pius V. made them the Councillors of the Pope, Urban VIII. gave them the title of Eminence, and Sextus V. settled their number at 6 bishops, 50 priests, and 14 deacons - 70 in all. They are nominated by the Pope, who has also the right of choosing some whose names he does not at once make known, but reserves to himself (in petto). If, however, he dies before declaring them, these nominations become void. The nomination does not give them the right to vote in conclave until the Pope has "opened their mouth." They do not leave Rome without leave of the Pope unless, being bishops, they have a see outside Rome. The Dean of the Sacred College consecrates the newly-elected Pope if he be not already a bishop. The special marks of a Cardinal are the red hat, the red biretta, and the red cassock. But a Cardinal belonging to one of the religious orders wears the habit of the order.