Of fundamental importance; crucial, pivotal. / (nautical) Of or relating to the cardinal directions (north, south, east and west).

(Roman Catholicism) One of the officials appointed by the pope in the Roman Catholic Church, ranking only below the pope and the patriarchs, constituting the special college which elects the pope. (See Wikipedia article on Catholic cardinals.)

(medicine) The study of the structure, function, and disorders of the heart.

A freshwater fish (Paracheirodon axelrodi, family Characidae), native to rivers in South America, popular as an aquarium fish.

A type of sweater or jumper that fastens up the front with buttons or a zipper, usually machine- or hand-knitted from wool.

(medicine) The primary or major symptom by which a diagnosis is made / (homeopathy) The particular symptom which is regarded most important for choosing the curing substance

A maritime traditional county of Wales, bordered by Pembrokeshire, Carmarthenshire, Brecknockshire, Radnorshire, Montgomeryshire and Merionethshire.

(baseball) A player on the St. Louis Cardinals team. / (American football) A player on the Arizona Cardinals team. / A player on a sports team at Stanford University.

A town in Ceredigion, Wales. / A surname.

(cardiology) The visual output an electrocardiograph produces