You mean "predecessor" (twice), "prequel" has a different meaning. It's (roughly) when the medium B is created after medium A, but is set earlier in time.
Both "prequel of A" and "sequel of A" imply "published later than A but set in the same universe", with "pre" and "se(q)" referring to the timelines, we can factor out "quel" to mean just that. I guess "Back to the future III" would be neither a sequel not a prequel, but definitely a quel.