Here's a list of commonly used acronyms to describe various elements related to RPG Maker.
QuoteABS - Action Battle System
A battle system from games like "The Legend of Zelda", "Secret of Mana", etc.
QuoteAMS - Advanced Message System
Message display system with many advanced options.
QuoteATB - Active Time Battle
A battle system from games like "Final Fantasy 4 - 9", etc.
QuoteATS - Advanced Timeflow System
A system that handles calendar, daytime and nighttime.
QuoteBABS - Blizzard Action Battle System
Same as Blizz-ABS.
QuoteBlizz-ABS - Blizzard Action Battle System
An action battle system made by Blizzard, currently exceeding every other ABS in configuration easieness, AI, non-lag and number of supported additional mini-features.
QuoteCA - Creation Asylum (www.creation-asylum.net)
A support forum for RPG Maker.
QuoteCBS - Custom Battle System
A term to describe any battle system other than the default.
QuoteCDS - Chaos Drive System
A system that allows character transformations. Now part of CLRS.
QuoteCMS - Custom Menu System
A term to describe any menu system other than the default
QuoteCP - Chaos Project (www.chaos-project.com)
The name of the game and the forum made by Blizzard.
QuoteCRLS - Chaos Rage Limit System
Chaos Drive System, Soul Rage System and Soul Limit System in one script.
QuoteDBS - Default Battle System
The default battle system from RMXP
QuoteDMS - Default Menu System
The default menu system from RMXP
QuoteDNS - Day & Night System
A system that handles the day and night cycle.
QuoteEXP - Experience Points
A value to describe how strong the character has become.
QuoteHP - Hit Points
A value to describe how much energy the character has.
QuoteMACL - Method and Class Library
A collection of more or less useful methods and classes.
QuoteMCL - Method and Class Library
Same as MACL.
QuoteMP - Magic Points (or Mana Points)
A value to describe how many points to spend on magic the character has left.
QuotePK v1.0 - Postality Knights (also called Dyna or Dynaemu)
The first illegal english translation of the Japanese version of RMXP. It's rather rare and hard to obtain.
QuotePKE v2.0 - Postality Knights Enhanced v2.0
The PK v2.0; an illegal english translation of the Japanese version of RMXP.
QuoteRM2k - RPG Maker 2000
An older version of RPG Maker.
QuoteRM2k3 - RPG Maker 2003
An older version of RPG Maker.
QuoteRMRK - RPG Maker Resource Kit (www.rmrk.net)
A support forum for RPG Maker.
QuoteRMVX - RPG Maker VX
The currently newest version of RPG Maker for the PC.
QuoteRMXP - RPG Maker XP
The most recent version of RPG Maker for the PC.
Quotermxp.org - RMXP.org (www.rmxp.org)
A support forum for RPG Maker.
QuoteRPGXP - RPG Maker XP
Same as RMXP.
QuoteRTAB - Real Time Active Battle
Same as ATB.
QuoteRTP - Run Time Package
A package of standard graphics and music.
QuoteSBS - Strategical Battle System
A turn-based battle system where players and enemies move around a battle map and execute actions. This system concludes tactical and strategical planning and sometimes battles take a lot of time to be fought. Similar systems can be found in commercial games like "Ogre Battle".
QuoteSDK v1.x - Standard Development Kit v1.x
A rewrite of the default RXMP to improve performance and compatibility. Performance was not improved and the SDK has only caused more incompatibility issues so far by separating SDK and non-SDK scripts.
QuoteSDK v2.x - Standard Development Kit v2.x
A new version of the SDK with more rewrites. Performance was decreased to improve compatibility. But SDK v2.0 is now even more incompatible with non-SDK scripts.
QuoteSLS - Soul Limit System
An Overdrive/Limit Break System based on the Soul Rage System. Now part of CRLS.
QuoteSP - Skill Points (or Spell Points)
Same as MP.
QuoteSRS - Soul Rage System
A system that mimics Ikari skills from "Lufia 2" for the SNES with enhanced possibilities. Now part of CRLS.
QuoteSSS - Skill Separation System
A system that can separate skills into "Black Magic", "White Magic", "Technics", etc.
QuoteSVB(S) - Side View Battle (System)
A battle system that shows the battle from the side. This system does not affect the type of battle (ATB, RTAB, etc.)
QuoteTBS - Tactical Battle System
A turn-based battle system where players and enemies move on a square tilemap and execute actions. This system concludes tactical and strategical planning and usually one battle takes a lot of time to be fought. Similar systems can be found in commercial games like "Final Fantasy Tactics".
QuoteTOA - Tons of Add-ons
The largest collection of little script snipplets with high compatibility.
QuoteUMS - Universal Message System
Same as AMS.