Equinoctial line Meaning, Definition & Usage

  1. noun the great circle on the celestial sphere midway between the celestial poles
    celestial equator; equinoctial; equinoctial circle.

WordNet


Definitions
  1. (Astron.), the celestial equator; so called because when the sun is on it, the nights and days are of equal length in all parts of the world. See Equator.

Webster 1913