TLAs: Are Common These Days

TLAs: Are Common These Days 150 150 IEEE EMBS

Three-Letter Acronyms (TLAs) are very popular, and can be found in almost everything written or spoken these days. Why? Perhaps it is because we are busy, lazy, or maybe there is just a fascination with things that come in threes. Most likely, we write or speak in TLAs because it makes our language more efficient at conveying information with the least possible cost. TLAs transform largely redundant information into a more expeditious form.

The dictionary defines an acronym as an abbreviation usually comprising the first letters of the words making up the name to be abbreviated. An acronym is to be distinguished here from an ordinary abbreviation that might contain letters from anywhere in the word to be abbreviated; these letters usually convey the important sounds of the original word. An acronym usually does not abbreviate just one word, nor does it hint to the sounds of the words abbreviated. Some places are known by three-letter abbreviations, not properly acronyms, such as STL (Saint Louis), ATL (Atlanta), and CLE (Cleveland). An acronym is usually composed of all upper-case letters, whereas an abbreviation may contain both upper-case and lower-case letters. Thus, Sgt. (Sergeant), Cpl. (Corporal), Inc. (Incorporated), and WVA (West Virginia) are three-letter abbreviations, but NBC (National Broadcasting Corporation), MLB (Major League Baseball), SLC (Salt Lake City), NYC (New York City), and LLC (Limited Liability Corporation) are all TLAs.

The allure of three: There is something appealingly special about things that come in threes. A three-legged stool is more stable on uneven ground than a stool with fewer or more legs; the length of a leg of a triangle can always be found from the dimensions of the other two; the Christian Holy Trinity comprises three members; and bad luck events are said by some to come in threes. In music, there is often an evenly spaced three-note modulation when changing keys. The transition between verses and choruses, or from line to line, is often made with a three-note run (for example, in Neil Diamond’s song “Sweet Caroline,” the words of the first line are “Sweet Caroline,” and then there is an unforgettable three-note “bum, bum, bum” before the second line, “Good times never seemed so good”). In sports, we have notable happenings in a “hat trick” for three goals made by the same player in a single game, a “trifecta,” which is a bet in which the person betting forecasts the first three finishers in a horse race in the correct order, and a “threepeat” when consecutive championships are won three at a time. In baseball, a batter is entitled to three strikes before being called out. In comedy, there is a rule of three, where a humorous one-liner is made up of two normal elements with an additional unexpected or exaggerated third element (as with the Amy Schumer 2017 quip, “This past year I’ve gotten very rich, famous, and humble.” The first two elements set up a pattern that is upset by the third, and adds the humor.) [1]. We even have special words for collections of three, such as “trilogy” for three writings and “triptych” for three pieces of art. There are many three-step processes for problem-solving, composed of recognition, diagnosis, and remediation. We have a saying that the “third time is the charm.” Most Americans have three names, and some former presidents were best known by their three-letter initials (FDR, HST, DDE, JFK, and so on). In “Hair,” the rock musical theater production, there is a song titled “Initials,” also known as “LBJ,” that pokes fun at TLAs in common use in the 1960s:

“LBJ took the IRT
Down to 4th Street USA
When he got there
What did he see?
The youth of America on LSD”

Three things seem to be especially easy to verbalize and to remember. So, that might explain why acronyms of three letters are so popular.

Three-word names and phrases are also popular. The appeal of three things extends even to political and commercial slogans. These phrases are always words, not TLAs, but comprising three words makes them easy to remember and particularly effective [2]–[5]. Many of these three-word slogans have passed easily into the vernacular without recognizing their original sources. Some of these are: “Black Lives Matter” (also with a TLA—BLM), “Peace with Honor” (Vietnam War slogan), “Read My Lips” (President George H. W. Bush), “Remember the Alamo” (from the Mexican–American War, 1846), “Remember the Maine,” (slogan for the Spanish–American War, 1898), “Save the Bay” (protecting the Chesapeake Bay), “Yes We Can” (Obama political slogan), “King of Beers” (Budweiser), “Breakfast of Champions” (Wheaties cereal), “We Try Harder” (Avis car rental), “Where’s the Beef?” (Wendy’s fast food), “Just Do It” (Nike athletic shoes), “I’m Lovin’ It” (McDonald’s fast food), “Imagination at Work” (General Electric), “Stronger than Dirt” (Ajax cleanser), and “Just Say No” (1970s anti-drug slogan).

Phrases of two coupled words with a total of three syllables also seem to roll particularly easily off the tongue. Illustrations of these are “space shuttle,” “sirloin steak,” “Burger King,” “hardware store,” and “funny joke.” Of note, also, is that, with few exceptions, all commercial radio and television broadcast stations in the USA are named with three-letter call signs [6]. 

This tendency toward three words that lend themselves to become TLAs has special meaning in my career. The airflow perturbation device (APD) is an instrument for noninvasive measurement of respiratory resistance [7]. I invented the APD and have used a good part of my career to develop it further and use it to determine respiratory responses to various respiratory challenges. Along the way, a number of graduate students helped immensely toward these goals.

For years after the conception of the APD, we called it a “perturbation device,” without the “airflow.” That is, until a graduate student of mine (Chin-Shing Lin) started calling it an APD [8]. APD is much easier to say than “perturbation device.” The TLA stuck, and it has been known as an APD ever since. 

TLAs should be easier to verbalize than those words that they stand for. TLAs can comprise any three letters, but those TLA letters with only one syllable names are most easy to say. The letter “W” is alone among the names of our alphabet letters with more than one syllable in its name. And, guess what: It has a three-syllable name (“duh-bul-you”). That is why it is harder to say TLAs with a “W” in them compared to other TLAs. Saying “W” out loud is so uneconomical to some that it has been sometimes colloquially pronounced with two syllables, (“dub-ya”). CWM (Country Western Music), DPW (Department of Public Works), DFW (Department of Fish and Wildlife), WWE (World Wrestling Entertainment), AWD (All Wheel Drive), and WSJ (The Wall Street Journal) do include “W,” but are not as easy to articulate as are other acronyms. In fact, it is easier to say “World Wildlife Fund,” with four or five syllables (depending on your accent), rather than the acronym “WWF,” with seven syllables. However, even with a “W” in the acronym WMD, it is still easier to say than “weapons of mass destruction” that it stands for.

TLAs of general use might include MIA (missing in action), RDA (recommended dietary allowance), LOL (laughing out loud, or lots of love), TMI (too much information), IRA (individual retirement account), DOA (dead on arrival), NIL (name, image, and likeness for college athletes’ business opportunities), SOP (standard operating procedure), NDA (nondisclosure agreement), EDT (Eastern Daylight Time, and its counterpart, EST, for standard time), GIF (graphics interchange format), NFT (nonfungible token, for a digital creation), CIP (clean in place, or change in plans), CDL (commercial driver’s license), POV (privately owned vehicle, or point of view), HOV (high occupancy vehicular highway lanes), CYA (cover your a**), FOB (freight on board), CEO (chief executive officer, and other corporate titles with similar TLAs), EDP (electronic data processing), IED (improvised explosive device), OEM (original equipment manufacturer), NCO (noncommissioned officer), VIP (very important person), OJT (on-the-job training), SOS (save our ship), JIT (just in time supply and inventory control), IAQ (indoor air quality), CYI (children and youth initiative, or can you imagine), CMA (Country Music Association), TED (technology, entertainment, design), OMG (oh my gosh), GMO (genetically modified organism), FYI (for your information), BTW (by the way), PAC (Political Action Committee), NAE (no antibiotics, ever, for poultry raised for human consumption), SNL (Saturday Night Live television program), and ABJ (American Bee Journal). Some of these are used so commonly that they are not defined when they appear in written form or when spoken to others; the reader or listener is expected to know what they mean without a definition. Interpretation is content-driven, especially when there are several possible meanings for the TLA used.

There are many governmental offices and agencies that are known best by their TLAs, including, but certainly not limited to EPA (Environmental Protection Agency), FBI (Federal Bureau of Investigation), FDA (Food and Drug Administration), HUD (Housing and Urban Development), TSA (Transportation Safety Authority), CDA (Chicago Department of Aviation), HOA (Home Owners Association), NGO (Non Governmental Organization), EWG (Environmental Working Group), WHO (World Health Organization), ILO (International Labor Organization), GOP (Grand Old Party), MCK (Minnesota Central Kitchen), BPD (Baltimore Police Department), CSI (Crime Scene Investigation), CIA (Central Intelligence Agency), IMF (International Monetary Fund), ISA (International Seabed Authority), EEC (European Economic Community), and MTA (Mass Transit Authority, or Metropolitan Transit Authority). 

Laws and governmental programs often go by their TLAs as a means to avoid having to articulate, or even remember, their full names. TVA (Tennessee Valley Authority), ACA (Affordable Care Act, also known as “Obamacare”), EEO (equal employment opportunity ), RFS (Renewable Fuel Standard), GPS (Global Positioning Satellite), SDI (Strategic Defense Initiative), ADA (Americans with Disabilities Act), CPI (consumer price index), GDP (gross domestic product) and its counterpart GNP (gross national product), MPA (marine protected area), and DEI (diversity, equity, and inclusion in the workplace) are among these. 

Medical TLAs provide shortcuts for busy health care personnel; some have been made popular by television commercials selling medicines for such conditions as UTI (urinary tract infection), DVT (deep vein thrombosis), AMD (age-related macular degeneration), and IBS (irritable bowel syndrome). Others include MBI (molecular breast imaging), MRI (magnetic resonance imaging), PET (positron emission tomography), CAT (computed axial tomography), EEG (electroencephalogram), ECG (electrocardiogram, and its German counterpart, EKG), TMS (transcranial magnetic stimulation), IVF (invitro fertilization), OTC (over the counter), SPF (sun protection factor), TLC (total lung capacity, or tender loving care), FEV (forced expiratory volume), RNA (ribonucleic acid), DNA (deoxyribonucleic acid), PVC (premature ventricular contractions, or poly vinyl chloride), IUD (intrauterine device), AZT [aZidothymidine, an antiretroviral medication used to prevent and treat HIV (human immunodeficiency virus)], LSD (lysergic acid diethylamide), BMI (body mass index, or brain–machine interface), ALS (amyotrophic lateral sclerosis), SAD (seasonal affective disorder), IAQ (indoor air quality), HMO (Health Maintenance Organization), PPO (Preferred Provider Organization) and IIT (integrated information Theory, a way to explain consciousness in physical objects. 

Companies, corporations, and other organizations are often known by their TLAs. TWA (Trans World Airlines), RCA (Radio Corporation of America), UPS (United Parcel Service), NPR (National Public Radio), PBS (Public Broadcasting System), CBS (Columbia Broadcasting System), ABC (American Broadcasting Company), MTV (Music TeleVision), NFL (National Football League), NBA (National Basketball Association), NHL (National Hockey League), IOC (International Olympic Committee), AFL (American Federation of Labor), CIO (Congress of Industrial Organizations), ILA (International Longshoremen’s Association), AAA (American Automobile Association), BGE (Baltimore Gas and Electric), and USS (United States Steel) are among these. There are also the ABA (American Bar Association, for lawyers), AMA (American Medical Association), and ADA (American Dental Association). Their counterpart, the American Psychological Association (APA), has an acronym that doesn’t seem quite right, with a “P” in place of a word starting with an “s” sound.

The energy giant Exelon Corporation does not need a TLA because its name already has the preferred three syllables. 

Many colleges and universities, especially ones with “State” in their names, are well known by their TLAs: LSU (Louisiana State University), OSU (Ohio State University, or Oklahoma State University), VMI (Virginia Military Institute), BYU (Brigham Young University), UMB (University of Maryland at Baltimore), and MTU (Michigan Technological University). Some academic degrees are known best by their acronyms: MFA (Master of Fine Arts), MBA (Master of Business Administration), and Ph.D. (Doctor of Philosophy, but not truly an acronym in the same sense).

Devices and materials are often known by their TLAs: SUV (sport utility vehicle), LED (light emitting diode), ATV (all-terrain vehicle), DVR (digital video recorder), SAM (surface-to-air missile), ABM (antiballistic missile), IoT (Internet of Things), DDT (dichlorodiphenyltrichloroethane), TNT (trinitro toluene), CFC (chlorinated fluorocarbon), ABS (antilock braking system), VOC (volatile organic compound), MOS (metal-oxide-semiconductor, or military occupational specialty), CRT (cathode ray tube), and, of course, APD. There is even a double TLA in the electronics field: MOS FET (metal oxide semiconductor field effect transistor), pronounced “mos fet,” just like it is spelled. 

As already noted, some TLAs have multiple definitions. The exact meaning of a TLA may depend on the audience to which the TLA use is directed. In fact, one website lists 214 definitions of the acronym AMC [9]. Obviously, the speaker (or writer) and the listener (or reader) must have synchronized interests in order to know which meaning is understandable. 

Airport designations are given by three-letter codes, but are not truly TLAs [10]: LGA (LaGuardia airport), SFO (San Francisco airport), ORD (O’Hare airport, standing for ORchard fielD, referring to the use of the property prior to building the airport), DFW (Dallas Fort Worth), SEA (Sea Tac Airport, serving Seattle and Tacoma, WA, USA).

Whereas most TLAs are spoken as the three letters that they comprise, some TLAs are given nicknames and pronounced as their own words, such as GUI (graphic user Interface), pronounced “gooey,” ICE (Immigration and Customs Enforcement), pronounced “ice,” or BBC (British Broadcasting Corporation), sometimes called “the beeb.” Notice that, in each of these cases, the spoken nickname requires less effort to articulate than saying the actual acronym, and certainly less effort than saying the words for which the acronym stands for. 

The above are just a few examples of the many TLAs that have peppered our language in recent years. The list is really so much longer, and most people could add at least a few without too much thought. We have gotten so used to using three-letter acronyms that they slip off our tongues without thinking about whether or not others understand what we are talking about. Perhaps there will come a time when all of our speech will consist of AMWs (abbreviated meaningful words).


  1. E. Broomfield, “Be (slightly) funnier,” Reader’s Dig., Oct. 2021, pp. 30–33.
  2. Three Word Phrases. Accessed: Aug. 15, 2021. [Online]. Available:
  3. Three Word Quotes. Accessed: Aug. 15, 2021. [Online]. Available:
  4. Advertising Slogans. Accessed: Aug. 15, 2021. [Online]. Available:
  5. Wikipedia. List of Political Slogans. Accessed: Aug. 15, 2021. [Online]. Available:
  6. Wikipedia. Call Signs in the United States. Accessed: Sep. 22, 2021. [Online]. Available: :text=Following%20a%20practice%20inaugurated%20in%201912%20when%20the,the%20west%2C%20and%20with%20%22W%22%20in%20the%20east
  7. C. G. Lausted and A. T. Johnson, “Respiratory resistance measured by an airflow perturbation device,” Physiol. Meas., vol. 20, pp. 21–35, Feb. 1999.
  8. A. T. Johnson and C. S. Lin, “Airflow perturbation device for measuring airways resistance of animals,” Trans. Amer. Soc. Agricult. Eng., vol. 26, no. 2, pp. 503–506, 1983.
  9. Meanings of AMC. Accessed: Aug. 20, 2021. [Online]. Available:
  10. B. J. Wilson. A Fun History of Airport Codes. Accessed: Aug. 15, 2021. [Online]. Available: