A bruise is a dark, tender mark on your skin that appears after you bump into something hard or get hit. When you bang your shin on a coffee table or fall off your bike, tiny blood vessels under your skin break open and leak blood into the surrounding tissue. That leaked blood is what creates the purple, blue, or yellowish mark you see.

Fresh bruises usually start out red or purple, then turn blue or black as the blood loses oxygen. Over the next week or two, as your body breaks down and reabsorbs the blood, a bruise changes to greenish-yellow before finally fading away. The more force behind the impact, the bigger and darker the bruise tends to be.

You can also bruise fruit by dropping or squeezing it too hard, creating soft brown spots. People sometimes use the word to describe hurt feelings: if someone laughs at your idea in front of the whole class, you might say it bruised your pride or that you have a bruised ego. Just like a physical bruise, hurt feelings can be tender for a while before they heal.