To cross something means to go from one side to the other. You cross the street when you walk from one sidewalk to the opposite one. A bridge crosses a river, connecting the land on both sides. Birds cross the sky as they fly overhead.

The word works in many situations. In a classroom, you might cross out a wrong answer by drawing a line through it. When someone crosses their arms, they fold them over their chest, sometimes when feeling stubborn or defensive. If two paths cross, they meet and intersect at a particular point.

Crossing can mean the act of going across something, like when early pioneers made the dangerous crossing of the Rocky Mountains in covered wagons. A pedestrian crossing is a marked place where people can safely walk across a road. The word also describes the place where things intersect: a railroad crossing is where train tracks cross a road.

When people talk about crossing a line, they mean going too far or breaking an unspoken rule. If your joke hurts someone's feelings, a friend might say you crossed the line, and it's a chance to apologize and do better.