From Longman Dictionary of Contemporary Englishcardinalcar‧di‧nal1 /ˈkɑːdənəl $ ˈkɑːr-/ noun [countable] 1 
RRCa priest of high rank in the Roman Catholic Church2 HBPa North American bird. The male is a bright red colour.3 HMNa cardinal number
RRCa priest of high rank in the Roman Catholic Church2 HBPa North American bird. The male is a bright red colour.3 HMNa cardinal numberExamples from the Corpus
cardinal• There were a cardinal and an aide to Garibaldi.• The sky was turning violet-dark, and a migration of cars with red taillights flew past us like flocks of cardinals.• Thus Innocent made four of his relatives cardinals, as opposed to Celestine's creation of only one.• The cardinal himself demurred, this prompting a noisy debate between the temporal and ecclesiastical peers.• The two cardinals were so loudly applauded that it was clear they represented the wishes of the majority.cardinalcardinal2 adjective [only before noun] BASICvery important or basic SYN fundamental Having clean hands is one of the cardinal rules when preparing food. an issue of cardinal importanceExamples from the Corpus
cardinal• Our policy has but one cardinal principle, and that is the Encyclopedia.• In Gandhi's view, its cardinal sin is the way it tolerates untouchability.• Other particles could take on names of the cardinal virtues.cardinal rules• Having clean hands is one of the cardinal rules of food preparation.Origin cardinal1 1. (1100-1200) Medieval Latin cardinalis, from Late Latin ( → CARDINAL2); 2. from the color of a cardinal's clothing cardinal2 (1200-1300) Old French Late Latin cardinalis, from Latin cardo “hinge” (= part that fastens something so that it can still move) 