(1) An image which has been turned upside down, with respect to the original, so that top and bottom are interchanged but right and left sides are not. (2) An image which has been turned upside down, with respect to the original, so that top and bottom are interchanged. Although the first definition is the one usually given, the second definition is the one commonly used. (3) An image such that motion from down-to-up in the scene causes an up-to-down motion in the image. An optical system consisting of objective lens and eyepiece such as is found in astronomical telescopes and some surveyor's telescopes produces an inverted and reversed image.