meta is talking about the current set of strategies that other players are using. For example, if someone figures out a very advantageous early attack, other p

meta is talking about the current set of strategies that other players are using. For example, if someone figures out a very advantageous early attack, other people will start to copy them. In response people will play defensively early on expecting the early attack. Then eventually people might not attack, and instead gather more resources early, since they expect their opponent to be defensive, etc etc. so as you play a lot, you learn the current meta strategies, and can adjust your strategy to give you a better chance of winning the game. that's "playing the meta" and why the meta shifts over time.