retrogradatio

A New Latin Dictionary by Charlton T. Lewis Ph.D. and Charles Short, LL. D.

rē̆trōgrădātĭo, ōnis, f. [retrogradior],

a going back , retrograding (late Lat.), Mart. Cap. 8, § 881: stellarum, Isid. Orig. 3, p. 83.