Acronym it. This has become such a problem that it is even evaluated at the level of medical academies such as the American Academy of Dermatology. Acronyms are often taught as mnemonic devices, for example in physics the colors of the visible spectrum are said to be "ROY G. BIV" ("red-orange-yellow-green-blue-indigo-violet"). They are also used as mental checklists, for example in aviation: "GUMPS", which is "Gas-Undercarriage-Mixture-Propeller-Seatbelts". Other examples of mnemonic acronyms are "CAN SLIM", and "PAVPANIC" as well as "PEMDAS". It is not uncommon for acronyms to be cited in a kind of false etymology, called a "folk etymology", for a
Planetary mnemonic Planetary mnemonic A planetary mnemonic refers to a phrase used to remember the planets and dwarf planets of the Solar System, with the order of words corresponding to increasing sidereal periods of the bodies. One simple visual mnemonic is to hold out both hands side-by-side with fingers spread and thumbs in the same direction, with the fingers of one hand representing the terrestrial planets, and the other hand the gas giants. The first thumb represents the Sun and asteroid belt, including Ceres, and the second thumb represents the asteroid belt and trans-Neptunian objects, including Pluto. An English-language mnemonic which was