Hotelling's Rule is a way to decide who should get a limited resource, like a piece of land or money. It is named after the economist Harold Hotelling who wrote about this idea.
Imagine two people who both want the same thing, like a beach ball. They can't both have it, so they have to find a way to decide who gets it. Hotelling's Rule gives each person a turn at getting the beach ball. First, the people decide who goes first. Then, that person can either take the ball for themselves or offer to share it with the other person. The other person then gets to choose to either accept the offer or not. The person who goes first will usually get the ball, but they might decide to split it if they think it's fair.
Hotelling's Rule helps people find a way to fairly decide who gets the limited resource. It makes sure that the decision is fair and that both people get a chance to have the ball.