Missed oppourtunity by the Marauders fandom to not make Regulus' shipname special word (don't know what you call that thing) regal instead of star.
Star was already widely in use for Sirius, but Regulus just had to have it too, to make things super confusing. Who is Starchaser? Starprince? Rosestar? Starkiller? We don't fucking know! It's one of them though! (Usually Sirius).
So I present to you the solution. Regal! Regulus is literally the root of the word regal, and it suits him more than star, because while he was the obedient and problem free child (the regal one if you will), we all know Sirius was the actual star of the family. Makes way for cooler shipnames that aren't confusing, like Regalmoon, Regalprince, Regalrose, Regalkiller, Regalflower, Regalcorn, and I'm just saying it's better and I don't think I need any more proof.