Your Glicko RD decides how your rating will increase or decrease after a chess game. It stabilizes after many games.
Glicko RD

A lower figure indicates your rating is more stable and less prone to deviate based on one result. Your opponent's rating also factors into this - the lower both your Glicko scores are the less impact one game will have on your chess ratings.

The Glicko RD is a measure of a 95% confidence interval for your true rating. If SR is your stated rating, your true rating is in the interval [SR-2RD, SR+2RD] with 95% confidence, where RD is your Glicko RD. it's one of those statistical things.

explain please,what Glicko RD means?