Crosswise means positioned or moving across something rather than along it. If you lay two pencils crosswise on your desk, they form an X or T shape instead of lying parallel. When you cut a carrot crosswise, you slice through it to make round coins rather than cutting lengthwise to make long strips.

The word describes anything that goes from side to side across something else. A fallen tree lying crosswise across a path blocks the way because it stretches from one side to the other. Railroad tracks run in one direction, but if you walk crosswise over them, you're stepping across the rails rather than walking along them.

In sewing and weaving, crosswise threads run perpendicular to the lengthwise ones, creating the grid pattern that holds fabric together. You might also see crosswise used in carpentry: boards placed crosswise provide support by going against the grain or direction of other boards. The opposite of crosswise is lengthwise, which means going along the longest dimension of something rather than across it.