ADVENTURERS!
Sometimes I’m stuck with some terms that I don’t recognize (english is not my first language) and I must search what does it mean. I’ve collected all abbreviations and acronyms about the world’s greatest roleplaying game.

1st  First edition D&D
2e  Second Edition D&D
3.5e 3.5  Edition D&D
3.X  refers to both or either of 3E, 3.5, above, Pathfinder, 13th Age, FantasyCraft or Mutants & Masterminds
3e  3rd Edition D&D
4e  4th Edition D&D
5e  5th Edition D&D
AC  Armor Class
AD&D, ADnD  Advanced Dungeons & Dragons
AD&D1  Advanced Dungeons & Dragons, 1st edition
AD&D2  Advanced Dungeons & Dragons, 2nd edition
AD&D2.5  Advanced Dungeons & Dragons, revised 2nd edition
AL  Adventure League
AMF  Anti-Magic Field
AoE  Area of effect
AoO  Attack of Opportunity
ASI  Ability score increase
atk  Attack
BA  Bonus Action
BBEG  Big Bad Evil Guy
Bbn  Barbarian
BD&D, BDnD  Basic Dungeons & Dragons, as opposed to Advanced Dungeons & Dragons
BECMI  Basic, Expert, Companion, Master, and Immortals Dungeons & Dragons Sets
BG  Baldur’s Gate
Bg or Bckgrnd  Background
BM  Beast Master (Ranger)
BR  Birthright campaign setting
Brd  Bard
Buff  Empower or strengthen an ability or character
BYOB  Bring your own booze or Bring your own bottle
CdG  Coup de Grace
CE  Chaotic Evil
CG  Chaotic Good
Cha  Charisma
Char  Character
Chargen  Character Generation
Charop  Character Optimization
Clr  Cleric
CN  Chaotic Neutral
Con  Constitution
CoS  Curse of Strahd adventure
cp  Copper pieces
CR  Challenge Rating
D&D, DnD  Any version of the D&D game
d% or d100  Two d10s die one as the 10s the other as the 1s
d10  A die of 10 sides
d12  A die of 12 sides
d20  A die of 20 sides
d20  System The system underlying 3e, v.3.5, Pathfinder and 4e
d4  A die of 4 sides
d6  A die of 6 sides
d8  A die of 8 sides
DC  Difficulty Class, the difficulty level of a skill check, ability check, or save
DDG  Deities & Demigods
Dex  Dexterity
DL  Dragonlance campaign setting
DM  Dungeon Master (see Game Master)
dmg  Damage
DMG  Dungeon Master Guide, any edition
DMS  Dungeon Master Screen
DnDNext  D&D Next 5e during it’s development/playtest, Codename Anduril
DoT  Damage over Time
DotMM . Dungeon of the Mad Mage
DPR  Damage Per Round
DR  Damage Reduction
Drd  Druid
DS  Dark Sun campaign setting
ECL  Effective Character Level
EE  Elemental Evil
e.g. (exempli gratia) for example
EK  Eldritch Knight
EL  Encounter Level
EP  Electrum Pieces
FF  Fiend Folio
FLGS  Friendly Local Game Store/Shop
FR  Forgotten Realms campaign setting
FRPG  Fantasy Role-Playing Game
Ftr  Fighter
FTW! or FTW  For the win!
FWIW  For what it’s worth
FYI  For your information
GGtR  Guildmaster’s Guide to Ravnica
GH  Greyhawk campaign setting
GM  Game Master
GP  Gold pieces
Grognard  An older gamer feels that the “old days” of gaming were better
GSL  Gaming System License
HotDQ  Hoard of the Dragon Queen
HP  Hit Points
HW  Hollow World campaign setting
i.e.   (id est) that is
IIRC  If I Recall Correctly
IMHO  In My Humble Opinion
Int  Intelligence
L&L, LL  Legends & Lore
LA  Level Adjustment
LE  Lawful Evil
LG  Lawful Good
LMoP  Lost Mines of Phandelver starter set adventure
LN  Lawful Neutral
LoS  Line of Sight
M:tG  Magic The Gathering
MC  Monstrous Compendium tome
Metagame  Using information you know as a player, but is unknown to your character
Mini  Plural minis; a miniature figurine
MM  Monster Manual
MMORPG  Massively Multiplayer Online Role Playing Game
Mnk  Monk
MoP  Manual of the Planes
MtG   Magic The Gathering
MtoF  Mordenkainen’s Tome of Foes
MUD  Multiple-user dungeon
Munchkin  Sometimes a synonym for power gaming
N, NN, or TN  Neutral, or True Neutral
NDA  Non-disclosure agreement
NE  Neutral Evil
Nerf  Weaken an ability or character through updates to the game rules
NG  Neutral Good
NPC  Non-Player Character
OA  Opportunity Attack
OA  Oriental Adventures rulebook
OC  Original Content
OD&D, ODnD  Old/original D&D
OGC  Open Gaming Content
OGL  Open Game License
OotA  Out of the Abyss adventure
OP  Over-Powered
OSR  Old School Revival
OTOH  On the other hand
Pal  Paladin
Pally  Paladin
PBeM  Play by email
PC  Player Character
PF  Pathfinder rule set
PH, PHB  Player’s Handbook, any edition
PM  Private Message
PO  Player’s Option books
PotA  Princes of the Apocalypse
pp  Platinum pieces
PP  Power Player
PrC  Prestige Class
PS  Planescape campaign setting
Psi  Psion/Psionic
PvP  Player versus Player
RAF  Rules as Fun.
RAI  Rules as Intended
RAW  Rules as Written
Rgr  Ranger
RL  Ravenloft campaign setting
RoD  Rage of Demons
Rog  Rogue
RoT  Rise of Tiamat
RP  Roleplay
RPG  Roleplaying Game
RPGA  Roleplaying Game Association network
SA  Sage Advice
SA  Sneak Attack
SCAG  Sword Coast Adventurer’s Guide
SJ  Spelljammer campaign setting
SKT  Storm King’s Thunder adventure
Sor  Sorcerer
sp  Silver Pieces
SR  Spell Resistance
SRD  System Reference Document
ST  Saving Throw
Stats  The statistical representation of a character
Str  Strength
TCG  Trading Card Game
THAC0 To Hit AC Zero (ref ad&d)
THP  Temporary hit points
Thx  Thanks
ToA  Tomb of Annihilation
ToD  Tyranny of Dragons adventure
ToH  Tomb of Horrors adventure
ToM  Tome of Magic
TPK  Total Party Kill
TRoT  The Rise of Tiamat adventure
TSR  Tactical Studies Rules. Original publishers of D&D
TWF  Two-Weapon Fighting
TY  Thank you
UA  Unearthed Arcana
UMD  Use Magic Device
UND  Underdark
VGtM  Volo’s Guide to Monsters
WDH Waterdeep Dragon Heist
WGtE Wayfinder’s Guide to Eberron
WH, WHF  Warhammer Fantasy
WIP  Work in progress
Wis  Wisdom
Wiz  Wizard
WoG  WG World of Greyhawk
WotC  Wizards of the Coast
Xbow  Crossbow
XGE  Xanthar’s Guide To Everything
XP  Experience Points