Meaning of cardinal sign

car'dinal sign'

Pronunciation: [key]
— Astrol. Astrol.
  1. any of the four astrological signs, Aries, Cancer, Libra, or Capricorn, that begin at the equinoxes and solstices, thus marking the beginning of the seasons: characterized by the attribute of strong initiative. Cf. quadruplicity.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.