Okay kiddo, so you know how sometimes you like to play with toys by yourself and you come up with stories and adventures in your head?
Well, a single player video game is kind of like that, but on a screen. It's a game that you can play all by yourself without needing anyone else to join in with you.
In a single player video game, you control a character or a little person on the screen and help them go on adventures, solve puzzles, fight bad guys or do other things depending on the game.
You can use a controller or keyboard to move your character and press buttons to make them do things like jump or attack. Some games even let you talk to other characters in the game, like if you were actually there with them.
It's just you and your character exploring a whole new world and having lots of fun together!