For the benefit of all members, in case of seeing an acronym or abbreviation you don't recognize - hopefully you shall find it here! Suggestions always welcome by commenting in this thread if we missed any.
Al Lutz - columnist and founder of MiceAge.
AA - Audio-Animatronic. Invention of WED, these are the cute little birds, swashbuckling pirates, animation characters, grim grinning ghosts and other characters you see in many of Disney's dark rides.
AL - Adventureland
AK - Animal Kingdom. The newest addition to the parks of Walt Disney World featuring Animals as the central attraction.
AP - Annual Passholders. Somebody who has an Annual Passport to Disneyland or Walt Disney World.
AIW - Alice In Wonderland
BB - Blue Bayou restaurant or Blizzard Beach (waterpark at WDW), depending on context
BLAB - Buzz Lightyear Astro Blasters. A futuristic shoot em' up ride featuring Buzz Lightyear from Toy Story fame.
BTMRR/BTM - Big Thunder Mountain Railroad. A rip-roaring coaster through the old west.
BSC - Blue Sky Cellar, preview center for the Disneyland Resort.
BTR- Big Thunder Ranch, petting area/craft barn and dining location at Disneyland.
BVS - Buena Vista Street, entry to California Adventure.
CBJ - Country Bear Jamboree, former Disneyland and current Magic Kingdom singing robotic bear show.
CC - Critter Country
CCT - Carthay Circle Theater, fine dining inside California Adventure.
CL - Cars Land (Disney California Adventure area, also called Radiator Springs)
CM - Cast Member, Disney employee
CP - College Program. See WDWCP.
CoP - Walt Disney's Carousel of Progress (attraction at Walt Disney World)
DAK - See AK
DCA - Disney's California Adventure.
DH - Disneyland Hotel.
DHS - Disney's Hollywood Studios (Formerly known as Disney MGM Studios in Orlando, FL)
DL - Disneyland. Walt Disney's original theme park located in Anaheim California. Opened on July 17th 1955 (some say July 18th) it is the center of the Disney Universe ... well, to us at least.
DLP - Disneyland Paris. Formerly known as EuroDisey, Disneyland Park is located outside of Paris France.
DLR - Disneyland Resort. The entire Disneyland Resort in Anaheim consisting of 2 parks (DL and DCA), 3 hotels and DTD (Downtown Disney)
DLRP - Disneyland Resort Paris. The entire Disneyland Resort in Paris consisting of 2 parks (DLP and WDSP) and hotels.
DTD - DownTown Disney. A shopping and dining experience located at the Disney resorts in Anaheim and Orlando.
DLRR- Disneyland RailRoad
Dustysage - The fearless leader of MiceChat.
DVC - Disney's Vacation Club - Disney's timeshare property
ECV-Electric Convenience Vehicle. A motorized vehicle disabled guests can rent to get around the park.
EE - Expedition Everest: Legend of the Forbidden Mountain
EMH - Extra Magic Hours. WDW Resort guests are invited for one hour in the morning or three hours in the evening for select attractions, shows and parks depending upon scheduling.
F! - Fantasmic. Night show located at Disneyland over TSI and the Disney-MGM Studios
FL - Fantasyland or Frontierland. Depending on the context of the post it could be either. If somebody is talking about a trip around a river or a ride on a canoe, it's most likely Frontierland. If somebody mentions Dumbo, Peter Pan, etc it's most likely Fantasyland
FNSV - Finding Nemo Submarine Voyage, Disneyland attraction.
FP - FastPass
FT - Luigi's Flying Tires, attraction inside Cars Land at Disney California Adventure.
GC- Grand Californian hotel, located at the Disneyland Resort.
GMR - Great Movie Ride, located at the Disney-MGM Studios
GRR - Grizzly River Run, located at California Adventure Park.
GH - Golden Horseshoe Saloon, Disneyland.
GR - Gumball Rally, a MiceChat Disneyland competition event.
GMWML - Great Moments with Mr. Lincoln (see also Lincoln)
Haunt - Knott's Scary Farm Halloween Haunt, beloved/frightening seasonal event at Knott's Berry Farm.
HHN - Halloween Horror Nights, themed Halloween event at Universal Studios Hollywood & Florida.
HKDL - Hong Kong Disneyland - Disney's newest park located in Hong Kong.
HM - Haunted Mansion
HMH - Haunted Mansion Holiday, a special Nightmare Before Christmas overlay for Disneyland's Haunted Mansion every October through December/early January
HB - Hungry Bear, eating establishment inside Critter Country. Home to ducks and excellent river views.
HHG - Hitchhiking Ghost(s), Haunted Mansion's most popular residents.
HISTA - Honey, I Shrunk the Audience. '4-D' film presentation, now extinct - played beneath Space Mountain at Disneyland.
IASW - It's a Small World. Walt Disney's famous cruise around the world which debuted at the 1964/1965 worlds fair.
IJA - Indiana Jones Adventure. Located exclusively at Disneyland this ride takes you on an adventure with the one and only Indiana Jones.
ITTBAB - It's Tough to Be a Bug. 3D movie based on Pixar's A Bugs Life located at AK and DCA.
JC - Jungle Cruise. Take a boat ride through the jungles of the world.
JH - Jolly Holiday Cafe, Main Street eating establishment in Disneyland.
JJ - Mater's Junkyard Jamboree, attraction inside Cars Land at Disney California Adventure.
JII - Journey into Imagination. Popular EPCOT attraction featuring Figment and Dreamfinder, now extinct.
KBF - Knott's Berry Farm, nearby western (mostly) theme park to Disneyland.
LMA - Lights, Motors, Action. A live stunt show at Disney Hollywood Studios and Disney Studios Paris.
LM:AUA - see also TLM (Little Mermaid dark ride)
Lincoln - Great Moments Mr. Lincoln, audio-animatronic historical presentation developed and conceived by Walt Disney for Disneyland.
M&G - Meet and Greet. Organized area/queued waiting zone to meet a character.
MC - MiceChat. You are here.
MGM - Disney MGM Studios. Walt Disney worlds 3rd theme park celebrating the US's greatest export ... Hollywood.
MI - Mysterious Island. Port of Call at Tokyo Disney Sea
MILF (no, not that one) - Monsters Inc Laugh Floor. Attraction at WDW's Magic Kingdom featuring the character from Monsters Inc in a stand-up comedy club.
MFW - Mickey's Fun Wheel.
M&F - Mickey and Friends parking lot.
MK - Magic Kingdom.
MM - Mickey Mouse/Minnie Mouse/Mortimer Mouse
MM+ - MyMagic Plus
MMC - Mickey Mouse Club
MNSSHP - Mickey's Not So Scary Halloween Party. Hard ticket event held at the Magic Kingdom and Disneyland during select nights in September and October.
MS - Main Street
M:S - Mission: Space
MSEP - Main Street Electrical Parade. The former nighttime spectacular parade shown at Disneyland. The parade can now be seen at the Magic Kingdom in Walt Disney World.
MVMCP - Mickey's Very Merry Christmas Party. Hard ticket event held at the Magic Kingdom during select nights in November and December.
NOS - New Orleans Square. Located exclusively at Disneyland and themed after old New Orleans. This land features such famous attractions as Pirates of the Carribean and Haunted Mansion.
ODV - Outdoor vending, or the carts where you buy ice cream bars, turkey legs, glow necklaces, etc.
PDJ - Pinocchio's Daring Journey
PFF - Princess Fantasy Faire, new expansion of Disneyland's Fantasyland.
PI - Pleasure Island. Walt Disney World's night club district located at Downtown Disney
PM - Peoplemover or Private Message
PO - Port Orleans, a resort hotel at Walt Disney World.
POTC - Pirates of the Carribean. The last attraction to be personally supervised by Walt Disney himself.
PPF - Peter Pan's Flight
PP - Paradise Pier
PPH - Paradise Pier Hotel
PPP - Pixar Play Parade
QS - quick-service, referring to a grab-and-go food counter location where your items are delivered to you after paying in a fast manner, and you find your own seating.
RCMC - Random Court of MiceChat
RNRC - Rock N' Roller Coaster. A fast limo ride through the streets and Freeways of Los Angeles starring Aerosmith. Located at MGM and WDS.
RSR - Radiator Springs Racers. "Test Track" type headliner attraction of the Cars Land/Radiator Springs area of Disney California Adventure.
RCT - Red Car Trolley, scenic transportation method inside California Adventure.
RDCT - Remember, Dreams Come True fireworks spectacular.
RRCTS - Roger Rabbit's Car Toon Spin, dark ride at Disneyland.
R2P2 - Redd Rockett's Pizza Port.
SBC - Sleeping Beauty Castle. Castle from Sleeping Beauty that is the gateway to Fantasyland at Disneyland and Hong Kong Disneyland.
Screamin' - California Screamin'. Roller Coaster at DCA modeled after the pier coasters of old.
SM - Space Mountain/Splash Mountain. Depends on Context.
SMGG - Space Mountain Ghost Galaxy. Seasonal overlay of the classic attraction during October at Disneyland and Hong Kong Disneyland.
SSE - Spaceship Earth.
SR - Single Rider. A option at some attractions allowing faster boarding for individuals riding alone.
ST - Star Tours
ST2 - Star Tours 2 (new version of Star Tours that opened at DHS May 2011 and Disneyland June 2011)
SWSA - Snow White's Scary Adventures
TDA - Team Disney Anaheim. The big yellow building behind Disneyland's ToonTown where management and corporate leaders work.
TDL - Tokyo Disneyland. Located in Japan, Tokyo Disneyland is considered to be one of the most beautiful parks in the Disney empire.
TDO - Team Disney Orlando. Walt Disney World marketing, management and design staff.
TDR - Tokyo Disney Resort. Consisting of TDL, TDS and on-site hotels.
TDS - Tokyo DisneySea. The newest addition to the Tokyo Disneyland resort.
TL - Tomorrowland. Futuristic world of tomorrow found at DL, MK, HKDL and TDL
TLM - The Little Mermaid: Ariels Undersea Adventure - dark ride at DCA opened in June 2011, 2013 in Magic Kingdom in Florida.
Toad - Mr. Toad's Wild Ride
ToT - Twilight Zone Tower of Terror. Themed drop ride found at DCA, MGM and WDSP. Named Tower of Terror at TDS.
TR - Trip report. A repot of a trip to anywhere. Could be the parks, the zoo, the beach or maybe even to the store.
TSI - Tom Sawyers Island
TSMM - Toy Story Midway Mania. Dark ride at both DCA and DHS themed to Toy Story featuring interractive 3D Carnival Games. Opened at both parks in Spring 2008.
TTA - Tomorrowland Transit Authority. Former WEDway peoplemover at MK.
TTC - Ticket and Transportation Center. Central location in WDW that sells tickets and provides monorail transport to MK and Epcot by Monorail or Boat (MK only).
TL - Typhoon Lagoon - Waterpark at WDW themed to the aftermath of a Typhoon.
TLT - Tomorrowland Terrace, quick service food location at both Disneyland and Tokyo Disneyland.
TT - Toontown
UoE - Universe of Energy, EPCOT attraction, now converted to Ellen's Energy Adventure but frequently called same name.
WDS - Walt Disney Studios. Located at the Disneyland Paris resort, it is the 2nd park along with Disneyland Park.
WDW - Walt Disney World. The Disney Companies orlando theme-parks consisting of the Magic Kingdom, Epcot, Disney MGM Studios and Animal Kingdom.
WDWCP - Walt Disney World College Program. Internship program for college students of all undergraduate majors from the United States and Internationally. See http://www.disneycollegeprogram.com for more information.
WL - Westernland. Tokyo Disneyland's version of Frontierland.
WoC - World of Color, nighttime water spectacular at Disney California Adventure.
WoL - Wonders of Life, extinct EPCOT pavilion.
WoM - World of Motion, extinct EPCOT pavilion/attraction.
WWTBAM - Who Wants to be a Millionaire - Play It!
MISC TERMS AND COMMON NON-DISNEY SPECIFIC
101 - an attraction was unexpectedly closed or had downtime.
IIRC - If I recall correctly.
FWIW - For what it's worth.
IMHO/IMO - In my honest opinion/In my opinion