An agent is the learner or decision-maker in RL. It could be a robot, a program, or even a player in a game.

The environment is everything the agent interacts with – the world or setting of the problem.

For example, the environment could be a maze, a game board, or any situation where the agent acts.

At each moment, the agent is in some state, which describes its current situation (like a location on a map). The agent then chooses an action (a move or decision).