cardinal

(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

serving as an essential component; "a cardinal rule"; "the central cause of the problem"; "an example that was fundamental to the argument"; "computers are fundamental to modern industrial structure"

being or denoting a numerical quantity but not order; "cardinal numbers"