Simple Definition:
An industry is a group of businesses that produce similar goods [things people buy, like cars or clothes] or services[activities people pay for, like haircuts or plumbing repairs].
For example, the automobile industry includes businesses that make cars, trucks, and other vehicles. The retail industry includes businesses that sell products to customers in stores or online.
Very Simple Definition:
An industry is a group of businesses that make or sell similar things.
For example, the automobile industry includes businesses that make cars and trucks. The retail industry includes businesses that sell products to customers.