The point on the celestial sphere, situated in the southern constellation Columba, away from which the solar system is moving relative to nearby stars; the point diametrically opposite to the solar apex; more fully "solar antapex". Also: the point on the celestial sphere away from which the earth is moving at any given moment in its orbital motion round the sun.
As a result of the motion of the solar system, stars appear to be converging on the antapex and diverging from the apex.
Mid 19th century; earliest use found in Reports of the British Association for the Advancement of Science. From anti- + apex.