Of fundamental importance; preëminent; superior; chief; principal.
- Of foremost importance; paramount: a cardinal rule; cardinal sins.
- Dark to deep or vivid red.
- Roman Catholic Church A high church official, ranking just below the pope, who has been appointed by a pope to membership in the College of Cardinals.
- A dark to deep or vivid red.
- A North American finch (Cardinalis cardinalis) having a crested head, a short thick bill, and bright red plumage in the male.
- A short hooded cloak, originally of scarlet cloth, worn by women in the 18th century.
- A cardinal number.