To sell means to exchange something you own for money. When you sell your old bicycle, you give it to someone else and they give you money in return. Stores sell groceries, toys, and clothes. Artists sell their paintings. Authors sell the rights to their books to publishers.

Selling is one of the most fundamental activities in any economy. Someone who sells things professionally is called a salesperson or seller. The person buying is the buyer or customer. Good salespeople understand what customers need and help them find the right product. They might work in a store, go door to door, or sell things online.

The word also means to convince someone to accept an idea. When you sell your parents on the idea of getting a dog, you're persuading them it's a good plan. A lawyer sells the jury on her client's innocence. In this sense, you're not exchanging goods for money, but you're still working to make someone believe in something.

Sometimes people say an event sold out, meaning all the tickets were purchased and none remain. You might hear that a concert or sports game sold out in minutes because it was really popular.