zodiac Meaning, Definition & Usage

  1. noun a belt-shaped region in the heavens on either side to the ecliptic; divided into 12 constellations or signs for astrological purposes
  2. noun (astrology) a circular diagram representing the 12 zodiacal constellations and showing their signs

WordNet

Zo"di*ac noun
Etymology
F. zodiaque (cf. It. zodiaco), fr. L. zodiacus, Gr. (sc. ), fr. , dim. of an animal, akin to living, to live.
Definitions
  1. (Astron.) (a) An imaginary belt in the heavens, 16° or 18° broad, in the middle of which is the ecliptic, or sun's path. It comprises the twelve constellations, which one constituted, and from which were named, the twelve signs of the zodiac. (b) A figure representing the signs, symbols, and constellations of the zodiac.
  2. A girdle; a belt. Poetic & R.
    By his side, As in a glistering zodiac, hung the sword. Milton.

Webster 1913