Reflection is a shape flipped over a line. When you look in a mirror objects look flipped. The line, over which the shape is flipped, becomes known as the line of reflection. Reflections shapes always keep the same size and shape. When a shape is slid to a new location in space, it is called a translation. Translations are a shape across the points of the object. If you slide something across the room to someone else, it’s a translation. The object must in the same direction for the same distance with n movement of the shape. For a movement to be a translation, the object must be moved with no reflecting or rotation of the object.
Al’shon Walker Geometry Blog 