A cardinal (Latin: sanctae romanae ecclesiae cardinalis, literally cardinal of the Holy Roman Church) is a senior ecclesiastical leader, an ecclesiastical prince, and usually (now always for those created when still within the voting age-range) an ordained bishop of the Roman Catholic Church. The cardinals of the Church are collectively known as the College of Cardinals. The duties of the cardinals include attending the meetings of the College and making themselves available individually or in groups to the Pope as requested. Most have additional duties, such as leading a diocese or archdiocese or managing a department of the Roman Curia. A cardinal's primary duty is electing the pope when the see becomes vacant. During the sede vacante (the period between a pope's death or resignation and the election of his successor), the day-to-day governance of the Holy See is in the hands of the College of Cardinals. The right to enter the conclave of cardinals where the pope is elected is limited to those who have not reached the age of 80 years by the day the vacancy occurs.

The entire group of cardinals is known as what?