Meaning

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

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

noun a variable color averaging a vivid red

originEtymology tree Latin cardō Proto-Indo-European *h₂el-der.? Proto-Italic *-ālis Latin -ālis Latin cardinālisder. Middle French cardinalbor. English cardinal From Middle French cardinal, from Latin cardinālis (“pertaining to a hinge, hence applied to that on which something turns or depends, important, principal, chief”), from cardin-, cardō (“hinge”) + -ālis, adjectival suffix.

Etymology from Wiktionary, CC BY-SA 3.0