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
Acronym shortened form, such as words with the middle omitted (for example, "Rd" for "road" or "Dr" for "Doctor"), an acronym is a word formed from the first letter or first few letters of each word in a phrase (such as "sonar", created from "sound navigation and ranging"). Attestations for "" in German are known from 1921, and for "acronym" in English from 1940. Although the word "acronym" is often used to refer to any abbreviation formed from initial letters, some dictionaries and usage commentators define "acronym" to mean an abbreviation that is pronounced as a word, in contrast to an