A pun is a joke that plays with words that sound alike or have multiple meanings. When someone makes a pun, they use a word in a clever way that creates two meanings at once, usually to make people laugh or groan.

For example, if someone says “I'm reading a book about anti-gravity and it's impossible to put down,” that's a pun. The phrase “put down” literally means to set something down, but it also means to stop reading. The joke works because both meanings fit at the same time.

Puns often use homophones, words that sound the same but mean different things. If you say “Time flies like an arrow, fruit flies like a banana,” you're punning on the two meanings of “flies”: moving quickly through the air versus the little insects.

People have mixed feelings about puns. Some find them hilarious and clever, while others respond with an exaggerated groan and an eye roll (though they're usually smiling when they do it). Shakespeare filled his plays with puns, and people have been making them for thousands of years. The word punster describes someone who makes puns frequently, and a pun-off is a competition where people try to create the best puns on a theme.