A freckle is a small, brownish spot on the skin. You might have a few freckles on your nose, or a lot of freckles across your shoulders and arms.
Most babies don't have any freckles, but people who are genetically predisposed to them and spend time in the sun tend to get freckles as children. People with pale skin, and sometimes red hair, have a tendency to get freckles and are more vulnerable to the sun's UV rays. If you have freckles, you should definitely use sunblock. When new freckles appear, you can say that you freckle.