He’s talking about retrograde motions and elliptical orbits or something.
There are no more uses of "retrograde" in the book.
Show samples from other sources
"You done knocked up mah precious baby again!" he boohooed in female plaint, his voice a heavenly facsimile—down to the perfect shading of falsetto—of that of some weak-witted and godforsaken wife and victim, blighted by wedlock, history and retrograde genes.