What is a motion?

Hint: The air that we breathe exhibits motion! Everything within the universe moves. We live in a universe that's in continual motion. The fundamental particle of a matter that's the atom is in constant motion too. Every physical process within the universe consists of motion of some sort. The motion can either be fast or slow, but motion exists.

Complete answer:
We can define motion because of the change of position of an object with reference to time. A book slumps a table, water flowing, rattling windows, etc. all exhibit motion. Motion is especially described in terms of the following terms:
Distance, Displacement, Speed and Time.
distance and displacement are the two things that are used to describe the change in position. Now if someone asks what the space between A and B is, we can’t provide a definite answer because it depends on the path taken. it may or might not be an equivalent for all three paths. except for displacement, we are able to always give a definite answer because it may be a line joining the 2 points. In other words, displacement is nothing but the shortest distance between the 2 points.
Speed and time are the measurements used to define the motion, where speed defines how fast something is in motion and time defines the instance for that motion.

Note:
All of us have noticed that different objects move differently. Some objects move during a curved path, some during a straight path and a number of others during a different way. according to the nature of the movement, motion is classed into three types as Linear Motion, Rotary Motion and the Oscillatory Motion