What are the allowed abbreviations in Scrabble?

One of the most prominent exceptions to Scrabble’s “no abbreviations” rule has to do with acronyms. In theory, acronyms are abbreviations and are thus unplayable. In practice, there is leeway. It is not absolute, and most acronyms are not valid plays: you can not just slap down YOLO or NASA without a potential loss of your turn. The trick is to locate the acronyms everyone forgets are not words.
LASER and MASER (it is like a laser, but microwaves are cast rather than light), SCUBA and SONAR, LIDAR, RADAR, and even the potty-mouthed SNAFU are all absolutely playable. You may have noticed that many of Scrabble’s playable acronyms have a scientific or military root which carries over to other abbreviations as well.
KILO and KBAR (short for kilobar, a measurement of force) are both playable. So is radio terminology like MAYDAY and WILCO and known military slang like AWOL.
Finally, the world’s most recognized abbreviation has its roots in this scrappy Officialese. Undoubtedly, some linguists believe the modest affirmative OK to be the world’s most popular word, appearing in a dozen spoken languages. It spread mainly through US military slang and, more significantly to our purposes, it is 100 percent legal in Scrabble.