designed to help correct or ameliorate the discomfort of disorders of the spine and joints: orthopaedic mattresses Collins English Dictionary - Complete & Unabridged 2012 Digital Edition Â© William Collins Sons & Co. Ltd. 1979, 1986 Â© HarperCollins
Definition of Immelmann. : a maneuver in which an airplane reverses direction by executing half of a loop upwards followed by half of a roll âcalled also Immelmann turn.
Illusory motion. The term illusory motion, also known as motion illusion, is an optical illusion in which a static image appears to be moving due to the cognitive effects of interacting color contrasts and shape position. Apparent motion is the most common type of illusory motion and is perceived when images are displayed in succession at a specific frame rate such as in a movie.