I think he means an easy explanation for them. A limit is a value that a function approaches. For example, you are lifting weights one day and you decide to increase the weights at small increments. Eventually you will approach a maximum amount of weight or what you may call your limit. If you go over that limit, you may decide to decrease weights in small increments until you reach the most weight that you can lift. So limits would be like the actual max amount of pounds you can lift. I hope this is precise and concise enough to help and give you a full understanding. This graph shows a limit as x approaches infinity. It's limit is whatever L is: Now, one major practical use of limits are derivates.