A host is someone who welcomes and takes care of guests. When your family has people over for dinner, whoever greets them at the door, makes sure they're comfortable, and serves the food is acting as the host. A good host thinks about what guests might need: a place to sit, something to drink, or help finding the bathroom.

The word also describes someone who runs a show or event. A game show host asks the questions and keeps things moving. A podcast host leads the conversation. The host of a party makes sure everyone's having fun and introduces people who don't know each other.

In biology, a host is an organism that supports a parasite or provides a home for another creature. A dog is the host for fleas. A person can be the host for the bacteria that cause strep throat.

Finally, a host can mean a large number of something: a host of problems or a host of possibilities.

When you're the host, whether of a birthday party or a lemonade stand, you're the one making others feel welcome and making sure everything runs smoothly.