Motion is movement or the act of moving from one place or position to another. When you wave your hand, ride your bike, or watch a bird fly across the sky, you're seeing motion.

In science, motion describes how objects change position over time. A ball rolling down a hill is in motion. A parked car has no motion. Scientists study motion carefully: they measure how fast things move (speed), what direction they're traveling, and what forces cause them to speed up, slow down, or change direction. Isaac Newton's famous laws of motion explain how objects behave when forces act on them.

The word also appears in other contexts. In meetings or formal groups, someone might make a motion to do something: a formal proposal that the group votes on. A senator might make a motion to pass a law. A club member makes a motion to change the meeting time.

When something happens in slow motion, it moves much slower than normal, like special camera effects in movies. When you go through the motions, you're doing something mechanically without real enthusiasm or attention. And when something is set in motion, it means starting a process or sequence of events.