AC: Ascalonian Catacombs.
AFK: Away from keyboard.
Alt: Alternative. May refer to a lesser used character.
AoE: Area of effect. If this site often means red (negative) or white (positive) circles or rectangles.
AP: Achievement. Often used in LFG messages to filter out inexperienced people. Not a very good metric but better than nothing.
Arah: The Ruined City of Arah.
Aura: Ticking PBAoE which follows the caster.
B: Back. Often used in combat to tell party go back / retreat.
Berserker: Gear with Power, Precision and Ferocity attributes. In LFG messages may also mean a high damage build.
Blasting: See Combos. Often refers using a blast finisher on fire, smoke or lighting field to stack might, stealth or swiftness.
Bouncing: Projectile that jumps to nearby targets. These can deal lots of damage if they bounce between two targets.
BRB: Be right back.
Build: Combination of gear, traits and skills.
Channeled: Attack lasts over time and needs to be constantly casted.
CM: Caudecus's Manor.
CoE: Crucible of Eternity.
CoF: Citadel of Flame.
Cone: Cone which often hit 5 targets.
Control: Control effect.
Dash: Mobile melee-skill. Single-target by default. May have additional effects before, during or after the dash.
Disc: Banner of Discipline.
DPS: Damage per second. Often refers to high damage builds.
DoT: Damage over time. Often refers to harmful AoEs.
Exp: Experienced. Often used in LFG messages. Actually definition varies from player to player. Can be quite easily faked if you pay attention and follow others.
F: Focus or fractal scale (difficulty).
FGJ: "For Great Justice!".
FotM: Fractals of the Mists.
Glass cannon: Build which focus on maximising damage output.
HPS: Healing per second.
Homing: Projectile which follows targets. These can't be avoided by movement.
HoT: Healing over time.
HotW: Honor of the Waves.
ICD: Internal cooldown. Some effects like traits, sigils or runes have an internal cooldown. After triggering there is a certain amount of time which has to pass before they can trigger again.
Leap: Mobile melee-skill. Single-target by default. May have additional effects before, during or after the leap.
LFG: See Looking For Group. An in-game tool which can be used to find party members. Please read and respect party requirements!
Kiting: See Combat. Refers to moving away from enemies to reduce damage taken.
LoS: Line of Sight. By running behind a corner you can force ranged enemies come close to you.
Lvl: Level. In dungeons this means a level requirement. In fractal his means a fractal scale requirement.
Main: May refer to the most used character.
Melee: Short cone which hits 1-3 targets.
Meta: Currently used effective builds. Often used in LFG messages to require a meta build.
MM: Minion master, a necromancer build.
NPC: Non-player character. Often refers to in-game allies.
Numbered attacks: Attacks-chained are listed with increased numbers (like Chop (1), Double Chop (2)). Often enemies continue chain if previous attack hits, in some cases they keep going regardless of success.
P#: Path for a dungeon. For example P1 is the first explorable path.
Pathing: Some enemies get a scripted order "Move to target" or "Move to location". "Move to target" ignores stealth which causes problems. See Other for more info.
PBAoE: Point blank area of effect. AoE which is centered at the caster.
Ping: Ctrl+Click or Shift+Click can be used to print (ping) items and skills on the chat. Often used in LFG messages to require everyone to ping their gear on the chat.
Projectile: Ranged attack which gets affected by anti-projectile skills. Projectiles have various travel times. Zig-zagging/side-stepping can be used to avoid slower ones. Requires line of sight.
PUG: Pick up group. A group of random players.
Pull: See Combat. Attacking enemies makes them follow you which can be used to move them to a better location.
Ranged: Ranged attack which doesn't get affected by anti-projectile skills. Usually instant travel time. Requires line of sight.
Res: Revive/resurrection. Used by dead people.
Returning: Projectile which returns back after reaching certain range.
Stacking: See Combat. Staying near each other. When staying together you share boons and can revive downed players fast.
SE: Sorrow's Embrace.
Spec: Combination of gear, traits and skills.
SR: Shadow Refuge.
Str: Banner of Strength.
TA: Twilight Arbor.
Tank: A build with high passive defence but low damage.
Tanking: Getting hit by easily avoidable attacks.
Ticking: AoE or effect which hits over time.
Trap: AoE which triggers when walked on.
Trash: Weaker enemies between or during the boss fights. Often skipped and ignored.
WB: Battle Standard.
WoR: Wall of Reflection.
WP: Waypoint. Often used to tell dead people to resurrect at a nearby waypoint.
Zerg: Huge amount of something (like players). People often use this when they meant Zerk.
Zerk: See Berserker.