cardinal - noun

(Roman Catholic Church) one of a group of more than 100 prominent bishops in the Sacred College who advise the Pope and elect new Popes

the number of elements in a mathematical set; denotes a quantity but not the order

a variable color averaging a vivid red

crested thick-billed North American finch having bright red plumage in the male

cardinal - adjective

• being or denoting a numerical quantity but not order
• serving as an essential component

cardinal - thesaurus

carmine   central   fundamental   key   primal   redbird