QCF = Quarter Circle Forward. Command is Down, Down/Forward, Forward.
QCB= Quarter Circle Backwards. Command is Down, Down/Back, Back.
HCF= Half Circle Forward. Command is Back, Down/Back, Down, Down/Forward, Forward.
HCB= Half Circle Backwards. Command is Forward, Down/Forward, Down, Down/Back, Back.
Full Circle Turn= Pressing each directional button in anti-clockwise order (Up, Up/Back, Back, Down/Back, Down, Down/Forward, Forward, Up/Forward, Up.)
Two Full Circle Turns= Pressing each directional button in anti-clockwise order twice.
 

Guilty Gear.
Punch- Punching attack (Square).
Kick- Kicking attack ( X ).
Slash- Attack with weapon (Triangle).
Heavy Slash- Strong attack with weapon (Circle).

Guard Motion- Guarding an attack (with Back).

Overdrives- Super Moves.
EX Overdrives- Super Moves in EX Mode.
Instant Kill- Killing move (press all buttons to move into Instant Kill Mode).

Street Fighter.
Light Punch- Jabbing attack (Square).
Medium Punch- Strong punch attack (Triangle).
Heavy Punch- Fierce punch attack (R1 generally. L1 in Marvel and Street Fighter games).
Light Kick- Jabbing attack (X).
Medium Kick- Strong kick attack (Circle).
Heavy Kick- Fierce kick attack (R2 generally. R1 in Marvel and Street Fighter games).

Super Combos- Super moves you can do when super bar is filled.
Level 3 Super move- Super Move you can only do when all 3 bars are full (on 3-level super bars [see X-ism on Street Fighter Alpha 3, or C-groove on Capcom VS SNK 2]).
Super Arts (street fighter 3)- Super moves you have to choose from to use in battle. You can only choose one.
Meteo Combos (Street Fighter EX games)- Really strong super moves you can do when bar is full.
Meteo Tag Combos (Street Fighter EX3)- Really strong super move you can do with your tag partner.