transformation

http://mrsdell.org/geometry/motion.html
A movement that doesn't change the size or shape of a figure is a rigid transformation.
Examples:

rotation, reflection, translation

translation (slide)

A movement of a geometric figure to a new position without turning or flipping it
Example:

 

 

 

 

reflection (flip)

The figure formed by flipping a geometric figure over a line of reflection to obtain a mirror image
Example:

 

 

 

rotation (turn)

A turning of a figure about a fixed point
Example: