noun: An acronym whose etymonic origin is incidental to the discussion at hand, and thus not worth mentioning or explaining in the context (or perhaps even worth remembering at all, for most speakers). Thus the word stands on its own with identity as a full-fledged word and not solely an acronym despite acronymic etymology, and (in the strongest cases, including laser, radar, sonar, lidar, and scuba) usually takes lowercased styling (because to capitalize it would represent undue emphasis on its etymonic origin). Relatedly, unlike with many other acronyms, spelling it out within a sentence is usually counterproductive to clarity and style.
