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Webster's Dictionary (1865)

Rĕ'tro-gra-dā'tion or Rĕt'ro-gra-dā'tion, n.

noun

n. [Fr. rétrogradation, Pr. retrogradacio, Sp. retrogradacion, It. retrogradazione, Lat. retrogradatio. See RETROGRADE.]

  1. The act of retrograding or moving backward.
  2. (Astron.) The apparent motion of the planets contrary to the order of the signs, that is, from east to west. Hutton.
  3. The state of being retrograded; a going backward; a decline.