Edge/Edging - Standing too close to the zombies meaning being vulnerable to an infection. If a leader calls out "Don't edge", he usually means get away from the box you're standing on or move a bit away from the edge
Nade - Grenade. (Grenades turn zombies on fire and slow them down. Good for when we are running away)
Failnades - Sometimes the explosion from grenades can boost zombies forward. This is a failnade. Always try to throw them so they explode above the zombies!
Defend/cover - Shoot away the zombies!
Backpaddle - This means walking/running backwards while shooting the zombies that are behind you
Doorhugging - This is when somebody is just standing at the next holdpoint (which is often a door) and not being useful, not helping to shoot away the zombies.
Lasers - A lot of maps have bossfights and a lot of bossfights have lasers. These are usually dodged by crouching or jumping. The height of the laser determines this. If a laser touches you, it's often an instant kill
Trigger - Most holdpoints/bossfights/teleports/doors etc requires a trigger. Most of the time, it's just walking up to these things but sometimes we have to solve a puzzle or pull a lever etc. If you're doorhugging, try to get the trigger
Bhop - Bunny hopping is a way of jumping in order to accelerate forward. Not specific to ZE but thought I'd explain it since it's a big part of ZE maps. Sometimes we have to go down ramps which zombies can bhop on
Materia/item - A lot of maps have special items both zombies and humans can pick up, with special effects. They can freeze/burn/push/slow/damage zombies and much more. Most of the time, you use an item by pressing "E" on your keyboard.
Overdefend - Over defending is when you stay and shoot the zombies for too long. This has consequences. Remember that the gamemode is escaping. Often we have to get into a bossfight before the doors close or get across a bridge quickly. A lot of maps also have teleports for the zombies and if you defend for too long, you might get teleported with them.