A checkup is a routine medical visit to make sure your body is healthy and working properly, even when you're not sick. During a checkup, a doctor or nurse measures your height and weight, checks your blood pressure, listens to your heart and lungs, and asks questions about how you've been feeling. They might also update your vaccinations or run simple tests.

The key word here is routine. Unlike going to the doctor because you have the flu or a broken arm, a checkup happens on a regular schedule, whether you feel fine or not. It's like a car's maintenance appointment: mechanics check things that seem fine now to catch small problems before they become big ones.

Doctors recommend checkups because they can spot warning signs of health issues before symptoms appear. A dentist might notice a tiny cavity during your dental checkup before it starts hurting. Your regular doctor might discover that you need glasses or that your iron levels are low.

The word can also be used more broadly. Your dad might do a security checkup on your house by testing locks and smoke detectors. A teacher might do a quick checkup on student understanding by asking a few questions mid-lesson.