cardinal

Concise Oxford English Dictionary © 2008 Oxford University Press:
cardinal/ˈkɑːdɪnl/

▶noun

• 1 a leading dignitary of the Roman Catholic Church, nominated by and having the power to elect the Pope.

• 2 a deep scarlet colour like that of a cardinal's cassock.

• 3 an American songbird of which the male is partly or mostly red and which typically has a crest. [Cardinalis cardinalis and other species, subfamily Cardinalinae.]

▶adjective of the greatest importance; fundamental: two cardinal points must be borne in mind.

– derivatives
cardinalate noun,
cardinally adverb,
cardinalship noun.

– origin OE, from L. cardinalis, from cardo, cardin- ‘hinge’; sense 1 has arisen from the function of such priests as ‘pivots’ of church life.