What "lead climbing" means in rock climbing

Lead climbing refers to a style of rock climbing where the climber ascends the route while clipping their rope into protection as they go. If they are placing their own protection as they go, then it is called trad climbing or traditional climbing. If the protection is already in place via bolts, then it is called sport climbing. This is in contrast to top rope climbing, where the rope runs from the climber up to an anchor at the top of the route and back down to the belayer. Lead climbing involves greater risk, as the climber is exposed to potential falls until placing the next piece of protection.