ELI5: Explain Like I'm 5

stock exchange

A stock exchange is a place where people buy and sell shares of ownership in companies. When you buy a share of a company, you become a 'shareholder' and own a small part of that company. It is like a store, where companies can sell a product (in this case, ownership) and buyers can buy it. When you buy or sell a share, it is done through a stock exchange.