Definition of cardinal
- cardinal Adjective Of fundamental importance; crucial, pivotal.
- cardinal Adjective Of or relating to the "cardinal" directions (north, south, east and west).
- cardinal Adjective Describing a "natural" number used to indicate quantity (e.g., one, two, three), as opposed to an ordinal number indicating relative position.
- cardinal Adjective Having a bright red color (from the color of a Catholic cardinal's cassock).
- cardinal Noun A number indicating quantity, or the size of a set, e.g., one, two, three. (See Wikipedia article on Cardinal number.)
- cardinal Noun An official in the Catholic Church, ranking only below the Pope and the patriarchs. (See Wikipedia article on Catholic cardinals.)
- cardinal Noun A songbird of the finch family, "Cardinalis cardinalis".
- cardinal Noun Any of various related passerine birds of the family "Cardinalidae". (See Wikipedia article on cardinal birds.)
- cardinal Noun A shade of scarlet associated with the colour of a Catholic cardinal's cassock.