DKT to Ed translation:

C-print="chromogenic print"--a print from a color negative. RA-4 prints are C-prints. LightJets on Fuji Crystal Archive are "Digital C-prints"--digital output on the same paper used to print from color negs.

R-print="reversal print", which would include Fuji, Agfa, and Kodak reversal print materials as well as Cibachrome, though Cibachrome is a very different kind of process.

RA-4 is just Kodak's designation for a chemical process for processing C-print paper, not unlike designations such as "E-6" or "K-14" or "C-41" for various film processes.