A zit is a small, inflamed bump on your skin, usually on your face, that happens when a pore gets clogged with oil and dead skin cells. Most people start getting zits around age 11 or 12, when hormones tell skin glands to produce more oil than before.

Zits are also called pimples or acne. They often appear on the forehead, nose, chin, or cheeks, though they can show up on your back or shoulders too. A zit might be red and sore, or it might have a white or yellowish center filled with pus (which is mostly white blood cells fighting bacteria).

Everyone gets zits sometimes. They're a normal part of growing up, not a sign that someone is dirty or doing anything wrong. The urge to pop or squeeze a zit is strong, but doing so usually makes things worse: it can spread bacteria, cause scarring, or turn one small zit into several angry red ones.

The word zit is informal and somewhat playful. In a doctor's office, you'd hear acne or pimple instead. But among friends, zit is the word most people use: “I woke up with a huge zit on my nose the day before picture day!”