Perspiration is the watery liquid your body releases through your skin when you're hot or working hard. You might know it better as sweat. When you run around at recess on a warm day, play an intense soccer game, or even feel nervous before giving a presentation, tiny holes in your skin called pores release perspiration to help cool you down.

Your body is remarkably smart about temperature control. When you get too hot, perspiration appears on your skin, and as it evaporates into the air, it carries heat away from your body, cooling you off. It's like how a wet towel feels cool on a hot day: the water evaporating takes heat with it.

The word perspiration sounds more formal and scientific than sweat. A doctor might ask about your perspiration patterns, while a coach might just yell, “You need to work up a sweat!” But they mean the same thing. People sometimes use the old saying “Horses sweat, men perspire, and ladies glow” as a joke about how we use fancier words to sound more polite, but really, everyone's body works the same way.