Officially Shortened Title

A newly premiered work has a long and/or elaborate title. If the show survives to become popular, however, a certain phenomenon is known to occur: This long and elaborate title is shortened to just half its original size, if that, and advertised as such.

While this is obviously done often among fandom, especially on the internet, this trope is specific to when the show is officially advertised with its shortened name in promotional material. The former can sometimes cause the latter, if the shortened name becomes much more well known than the full title. Other legitimate causes include events within the show or in real life necessitating a change.

Other reasons could be that perhaps the long title served to attract attention to the series and, mission accomplished, can go to a shorter title. Or perhaps network executives thought Viewers are Morons and wouldn't pay attention to or be able to read a long title. This has a mundane application as well: Advertising time is extremely expensive, so the less time they have to spend saying the name of the recognizable title the better.

Portmanteau Series Nickname is a related trope, mostly applying to Japanese-language works.

Anime & Manga

 * Scrapped Princess has "SutePuri," an abbreviation of "Suterareta Purinsesu" (Abandoned Princess) in its eyecatches. Translated in English subtitles as ScraPri.
 * Cardcaptor Sakura became Cardcaptors.
 * Tengen Toppa Gurren Lagann to Gurren Lagann when brought to the U.S.
 * Katekyo Hitman Reborn is known as simply Reborn! in the United States.
 * Futari wa Pretty Cure is only known to most people as just Pretty Cure.
 * The title of Top o Nerae! Gunbuster was a play on another series called Ace o Nerae! -- When it was adapted for US audiences, it became known as simply Gun Buster.
 * Kare Kano had its real title (His and Her Circumstances) relegated to sub-title when it crossed the Pacific.
 * Kochikame is short for Kochira Katsushika-ku Kameari Koen Mae Hashutsujo, which translates to This Is the Police Station in Front of Kameari Park in Katsushika Ward.
 * When Kodomo no Omocha was dubbed in America, it was called Kodocha.
 * Ore no Imouto ga Konna Ni Kawaii Wake ga Nai is sometimes called Oreimo on official products, and for the English release.

Film

 * How to Train Your Dragon is called in the commercials "Dream Works' Dragons."
 * The fourth Teenage Mutant Ninja Turtles movie had its title changed to TMNT.
 * Zack and Miri Make a Porno was usually advertised as just Zack and Miri. This is an interesting case in that the abbreviation had nothing to do with the title being too long; there are just places where you can't get away with referencing porno.
 * Inverted and in The Return of Hanuman, as its former name is Hanuman Returns.
 * Independence Day was also marketed as "ID 4" (4 being a reference to the 4th of July).
 * Dr. Strangelove, or How I Learned to Stop Worrying and love the Bomb.
 * The Disney Direct to Video film Lilo and Stitch 2: Stitch has a Glitch is simply known as Lilo and Stitch 2 in the actual film.
 * Similarly, The Emperor's New Groove 2: Kronk's New Groove, is simply referred by its subtitle.
 * Before it was released onto VHS and DVD, The Great Mouse Detective was actually originally entitled The Adventures of the Great Mouse Detective.
 * Posters for Mission Impossible III shortened the title to "M:i:III". As a result, Stephen Colbert made a Running Gag out of pronouncing it "Meeeeeeeeee".

Literature

 * The book On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, known today simply as On the Origin of Species or even just Origin of Species.
 * ZerothLaw: many of Shakespeare's plays are known by shorter versions of their titles, such as The Famous History of the Life of King Henry the Eight. The original titles (per the first quarto publications) are even longer. See also In Which a Trope Is Described.
 * Frankenstein; or, The Modern Prometheus is often known simply as Frankenstein or Mary Shelley's Frankenstein. It's commonly done with old books which follow the format of giving a title followed by 'or' and an alternative description of the content.

Live Action TV

 * 3rd Rock From the Sun eventually became Third Rock
 * Eight Simple Rules was originally Eight Simple Rules for Dating My Teenage Daughter. Though this case was justified a bit by the death of John Ritter, who played the father on the show.
 * Americas Funniest Home Videos is now known as AFV
 * Two Guys a Girl And A Pizza Place became Two Guys and a Girl. In fact, the Two Guys and A Girl trope page even mentions the series because of the likelihood of people looking for the show finding it. Like Eight Simple Rules, though, this was justified because there was Character Development and the Guys no longer worked at the titled Pizza Place.
 * Emmerdale Farm became Emmerdale. This was because the focus of the series had moved from the farm itself to the nearby village (which was originally called Beckindale, but was renamed shortly before the title change).
 * Zoey, Duncan, Jack and Jane became Zoe.... The commercials called it "Zoe dot dot dot".
 * Buffy the Vampire Slayer's name was never officially changed, but network promos shortened it after a while to just Buffy.
 * Studio 60 On the Sunset Strip was likewise shortened in promos to Studio 60.
 * Most of the "Late Show with..." become known by their host.
 * The now-forgotten Britcom Lollipop Loves Mr. Mole was renamed Lollipop for its second (and last) short season.
 * Absolutely Fabulous = Ab Fab
 * Lock Stock, The short-lived series of the film Lock Stock and Two Smoking Barrels.
 * Monty Python's Flying Circus became merely Monty Python in its final season without John Cleese.
 * Degrassi the Next Generation became just Degrassi starting in season 10, because all of that particular generation had moved on from the titular High School.
 * Inverted with Hannah Montana, which was adapted for and marketed to Japanese audiences as Secret Idol Hannah Montana.
 * Also inverted with the fourth and final season, billed in the US as "Hannah Montana Forever."
 * Before NCIS aired, it was branded as Navy CIS. Then CBS decided to change it to Navy NCIS for all of season one. CBS's reasoning for it, despite Donald P Bellisario's protests, wanted to attract new viewers who didn't know the acroynm and not have it be related to CSI. You read that right, NCIS was called Navy Naval Criminal Invesigative Service for an entire season. Needless to say, the title was eventually shortened because of how successful the first season was.
 * Hiroshi Sekiguchi's Tokyo Friend Park II was often referred to as Tokyo Friend Park II (although Hiroshi Sekiguchi remained host for the show's entire run from 1994 to 2011), and the show got a new logo at the start of its 5th season (April 1998) which read merely "TFP2", albeit often accompanied by the show's full title in smaller lettering underneath.
 * Misshitsu Nazotoki Variety Dasshutsu Game DERO! (roughly "Solve a Variety of Puzzles Behind Closed Doors: Escape Game DERO!") had a simpler version of its logo which simply read "Dasshutsu Game DERO!"; this version of the logo had been in use since the pilot episode. Meanwhile, the show would often get referred to as simply "DERO!".
 * Likewise, its Spiritual Successor Takara Sagashi Adventure Nazotoki Battle TORE! (roughly "Treasure Hunt Adventure: Puzzle Battle TORE!") also has a version of its logo which reads just "TORE!", and the show is often referred to as just "TORE!" as well.
 * Parks and Recreation is advertised as Parks and Rec.

Music

 * Oingo Boingo was originally The Mystic Knights of the Oingo Boingo, and later became just Boingo.
 * The Justified Ancients of MuMu shortened their name to J.A.M, but then had to change their name to The KLF because there was already a (rather well known) band called The Jam
 * Tyrannosaurus Rex became T. Rex when they went electric.
 * MGMT used to be "The Management".
 * Havalina Rail Co shortened their name to Havalina after several band members left.
 * Chicago was originally called Chicago Transit Authority, but the real Chicago Transit Authority was not amused and threatened to sue, so they shortened it.
 * The Grateful Dead later changed their name to The Dead when they had reunited without the late Jerry Garcia.
 * Jefferson Starship (originated from Jefferson Airplane) became Starship.
 * Savatage's first Rock Opera is formally known by the band as Streets, as they were unhappy that Executive Meddling forced the official title to be Streets: A Rock Opera.
 * Big Audio Dynamite II (formerly Big Audio Dynamite before some members left) became Big Audio for an album.
 * Wire became Wir for one album out of respect of drummer Robert Gotobed, who fired himself when he came to the realization that a drum machine could do his job better than he could.
 * The 21st-century revived Dexys Midnight Runners is just Dexys.

Theatre

 * Karel Capek's RUR. The "long" title, Rossum's Universal Robots, was only the subtitle in the first edition.

Video Games

 * Of the Bemani games, Guitar Freaks and Drum Mania are often collectively referred to as "GitaDora" (taking the first two katakana of each title) even on Konami's official site.
 * Some directories of the Wangan Midnight Maximum Tune official websites refer to the game as "Wanganmaxi."
 * When Game Boy RPG Pocket Monsters got to be quite popular, it started going by its Portmanteau Series Nickname, Pokémon. The rest is history.
 * Possible trademark complications in the US with Monster In My Pocket may also have had something to do with it...
 * Also, the shortened form appeared in-game even in the first Japanese release due to character limitations.
 * The Call of Duty spinoff series Modern Warfare began with Call of Duty 4: Modern Warfare, but the sequel is generally referred to simply as Modern Warfare 2 in the game and advertising, with Call of Duty only remaining on the box for brand recognition.
 * The Contra series was briefly shortened to just "C" when Konami was trying to distance the games from the Iran-Contra affair that occurred shortly before the first arcade game's release. As a result, the NES version of Super Contra was retitled to Super C, while the Game Boy Contra game was renamed Operation C.
 * The Japanese version of the Nintendo Entertainment System (NES) is officially called the Family Computer, but is better known as the Famicom. However, its successor is officially named the Super Famicom and not the "Super Family Computer". Averted with its western counterpart, which is officially named the Super Nintendo Entertainment System and commonly abbreviated as the Super NES.
 * King of Fighters is shortened to "KOF" on the Maximum Impact games.
 * Namco's Family Stadium series of baseball games officially became known as Famista beginning with its fourth Famicom installment (Famista '89).
 * The full title of SD Snatcher is Super Deform Snatcher, but this is displayed less prominently.
 * Super Mario World was originally known as Super Mario Bros. 4: Super Mario World.
 * And Yoshis Island was originally known as Super Mario World 2: Yoshi's Island.
 * And Wario Land was originally known as Super Mario Land 3: Wario Land.

Truth in Television

 * Originally known as the Scholastic Aptitude Test and Scholastic Assessment Test, "SAT" no longer stands for anything.
 * Similarly, "ACT" was originally an acronym for the American College Testing program.
 * Neither does "KFC" mean anything, formerly known as Kentucky Fried Chicken. This happens to acronyms with surprising frequency, actually.
 * The United Kingdom of Great Britain and Northern Ireland is generally known as the United Kingdom or UK. Of course, that abbreviation is probably a contributor to a certain trope.
 * Similarly, the United States of America are often simply the United States, America or the US (with an optional A for America).
 * Take it away, Loading Ready Run.
 * Also, Mexico's official name is Estados Unidos Mexicanos (Mexican United States), there was a congress proposal some years ago to legally change it to Mexico, but it wasn't approved.
 * The Kingdoms and Lands Represented in the Imperial Council and the Lands of the Holy Hungarian Crown of Saint Stephen never quite got the hang of it: their official short name, Austria-Hungary, was still quite a mouthful.
 * Federal Express officially changed their name to "FedEx" because "that's what everyone called us anyway."
 * AT&T was founded more than a century ago as the American Telephone and Telegraph company. When the company changed names in 1984, this was formally shortened to AT&T.
 * The College of the Blessed Virgin Mary, Saint John the Evangelist and the glorious Virgin Saint Radegund, near Cambridge is typically known by the shorter name of "Jesus."
 * A great number of churches and religious institutions the world over have the same thing going on; rarely does "the Evangelist" appear in the name of a church dedicated to one of Saints Matthew, Mark, Luke or John - and in the latter case, since a church might be dedicated to either "St. John the Evangelist" or to "St. John the Baptist," it might be a good idea to keep that around. And then there are the other designations. "St. John's Cathedral" in Winnipeg, Manitoba, is actually "The Anglican Cathedral Church of the Parish of St. John the Evangelist." Yikes.
 * The American public radio station, NPR, which was originally short for National Public Radio, changed their name officially to NPR in July 2010. They did it because "they are not just radio anymore" (they also do podcasts now). Not really a big deal since everyone called it "NPR" anyway.
 * Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch is a town on the island of Anglesey, Wales - many locals and visitors shorten it to Llanfairpwllgwyngyll, and the Highways Agency now write Llanfair PG on their road signs - presumably to save on paint.
 * Royalty. "Her Majesty, Queen Elizabeth the Second," is, according to The Other Wiki: Her Majesty Elizabeth the Second, by the Grace of God, of Great Britain, Ireland and the British Dominions beyond the Seas Queen, Defender of the Faith, Duchess of Edinburgh, Countess of Merioneth, Baroness Greenwich, Duke of Lancaster, Lord of Mann, Duke of Normandy, Sovereign of the Most Honourable Order of the Garter, Sovereign of the Most Honourable Order of the Bath, Sovereign of the Most Ancient and Most Noble Order of the Thistle, Sovereign of the Most Illustrious Order of Saint Patrick, Sovereign of the Most Distinguished Order of Saint Michael and Saint George, Sovereign of the Most Excellent Order of the British Empire, Sovereign of the Distinguished Service Order, Sovereign of the Imperial Service Order, Sovereign of the Most Exalted Order of the Star of India, Sovereign of the Most Eminent Order of the Indian Empire, Sovereign of the Order of British India, Sovereign of the Indian Order of Merit, Sovereign of the Order of Burma, Sovereign of the Royal Order of Victoria and Albert, Sovereign of the Royal Family Order of King Edward VII, Sovereign of the Order of Merit, Sovereign of the Order of the Companions of Honour, Sovereign of the Royal Victorian Order, Sovereign of the Most Venerable Order of the Hospital of St John of Jerusalem.
 * QVC is trying to rebrand itself as the "Q."

Other

 * G4 and Tech TV merged into G4Tech but later shortened it to G4 again.
 * Game Show Network was shortened to GSN.
 * The Young Men's Christian Association (YMCA) officially shortened it's name to "The Y".
 * Technically that's not actually shorter- matter of fact, it's longer if you count the space(!)

Western Animation

 * Nickelodeon does this in advertising for some of their own shows.
 * Avatar: The Last Airbender is usually referred to as simply Avatar ; however, the live-action movie is officially titled simply The Last Airbender, in order to avoid confusion with the James Cameron film Avatar.
 * Spongebob SquarePants is usually referred to as Spongebob
 * El Tigre the Adventures of Manny Rivera is simply El Tigre
 * Most commercials for Dexters Laboratory reruns (back when they actually aired the reruns) called the show simply Dexter's Lab. Even before that, the lyrics to the show's ending theme called it "Dexter's Lab."
 * The Total Drama series are all abbreviated: TDI, TDA, and TDWT.
 * Even the dropped name Total Drama the Musical was shortened to TDtM.
 * Adventure Time with Finn and Jake is officially just Adventure Time now. (Not like anyone called it by its full name anyway.)
 * One episode of The Simpsons where Marge Simpson was hated by most of Springfield for being a protecting mother had its episode title shortened to "Marge vs. Everyone" because its original title was too long.