What does RAG mean? I’m interested because I have tried to play a chess game purely through chat and my experience is that GPT 3 always forgets what is happenin

What does RAG mean? I’m interested because I have tried to play a chess game purely through chat and my experience is that GPT 3 always forgets what is happening in the game and wants to make illegal moves. I guess if there was a format (maybe PGN?) then maybe it could draw on some of its experience.