retrogrationn.

1567 W. Bourne Almanacke & Prognostication sig. Dii So doth all the seuen lightes or Planetes, except that it be in their retrrogration [sic], but the Sunne and the moone be neuer retrograte.

1644 W. L. Med. for Malignancy 30 All their proceedings, writings, or actions, in the time of this his Majesties peregrination, or rather retrogration, are al illegitimat.

1705 C. Purshall Ess. Mechanism Macrocosm xvi. 111 Again Saturn has a longer Space of Retrogration than Jupiter.

1830 H. H. Harte tr. P. S. de Laplace Syst. World I. 327 The cause of the differences which are observed in the quantity and duration of the retrogrations, arises from the ellipticity of the orbit.

1918 Amer. Med. Oct. 689 Racial degeneracy and retrogration will not result if there is no skull type mixing after peace is declared.

1996 Oceanogr. Lit. Rev. 43 458/2 The study has revealed that the coast has not undergone any significant progradation or retrogration during the past two decades.