A lemon is a yellow citrus fruit with sour juice. Lemons have been used by humans for more than two thousand years to flavor food and drinks.

A lemon can also refer to something that turns out to be defective or constantly broken, especially a car. If a family buys a used car that keeps breaking down no matter how many times it gets repaired, they might say they got stuck with a lemon. The engine sputters, the air conditioning fails, and something new goes wrong every week.

The term comes from the sour, disappointing taste of biting into a lemon when you expected something sweet. Many states have lemon laws that protect consumers who accidentally buy defective cars, requiring manufacturers to replace the car or give a refund.