1 .. translation is a kind of movement. When an object moves, the direction and distance between any two points on the object from one point to another are constant.

2. Rotation is the movement of an object, and the distance between each point and the same point is constant, which is called rotation around this point, and this point is called the rotation center of the object.

3. Therefore, it doesn't necessarily rotate around an axis.

4. Translation and rotation are aimed at rigid bodies, so the distance between any two points remains unchanged when an object moves and will not become its mirror image.

The motion of a point can always be regarded as translation.