MA - Main Assist
MT - Main Tank
Xtarget - Extended Target (Referencing the extended target window)
GD - Great Divide
EW - Eastern Wastes
ToV - Temple of veeshan for zone or Torment of velious for (recent) xpac
CoV - Claws of Veeshan
CS - Cobalt scar for zone or Customer Support
WW - Western Wastes
ST - Sleepers Tomb for zone - or Single Target (not Area of Effect AOE) damage
This list would likely be impossibly long - prolly better just askin as you find stuff you're not sure on