A guest is someone who visits another person's home, attends an event, or stays somewhere by invitation. When you go to a friend's birthday party, you're a guest in their home. When your grandparents visit for the weekend, they're guests in your house.

The word often involves an expectation: hosts treat guests with courtesy and generosity, and guests are respectful and appreciative. This mutual respect is sometimes called hospitality. If you're a guest at someone's dinner table, you might wait to be offered seconds rather than helping yourself. If you're hosting guests, you might give them the comfortable chair or let them choose which movie to watch.

In hotels and restaurants, paying customers are often called guests rather than just customers, a way of emphasizing that they should be treated with special care. A guest speaker visits a classroom or event to share expertise. A guest appearance is when someone shows up on a show they're not regularly part of.

The phrase be my guest means “go ahead” or “help yourself.” If someone asks, “May I borrow your pencil?” you might say, “Be my guest!” The opposite of a guest is a host, the person doing the inviting and welcoming.