Of fundamental importance; preëminent; superior; chief; principal.

the cardinal bird, also called the northern cardinal.

North, South, East or West directions only.

crested thick-billed North American finch having bright red plumage in the male

serving as an essential component; "a cardinal rule"; "the central cause of the problem"; "an example that was fundamental to the argument"; "computers are fundamental to modern industrial structure"

Related to the Phases, those which represent the compass-points: North-Phase 1, East-Phase 22, South-Phase 15 and West-Phase 8. These four Phases exhibit special configurations of the Faculties, where the Oppositions and Discords come together, and represent crucial points in the cycle. In terms of incarnation, Phases 1 and 15 are non-corporeal incarnations, while Phases 8 and 22 are crises for the soul. See The Cardinal Phases and the Triads.

Referring to the four main points of the compass: North, South, East and West

chief, fundamental

Fundamental, of first importance. E.g. marks - North, South, East, West

The Cardinals or Cardinalidae are a family of passerine birds living in North and South America.