The following site seems to be pretty good at collecting those terms and explaining them:
For instance, two in particular Sean mentioned are as follows:
- buff: (verb) To cast spells or perform some action on oneself or someone else to increase their stats or abilities. (See also "debuff") "I'm buffed and ready to go."
- buff: (noun) Spells or effects that increase stats or abilities. (See also "debuff") "I need a strength buff."
In wizard 101, that would be casting beneficial spells on anyone. The sorcerer is good at buffing other players. Necromancers have an excellent debuff that puts a -20% damage on all monsters in play.
Here's another term that Sean asked about:
farm: to safely collect experience or other bonuses from monsters or other characters (by killing them)
In Wizard 101 you sometimes have to "farm" certain bosses that are well below your level to get a certain pet or wand you might want to collect.
Let me give you an example of how this might work in reverse: One time I was used by a lower level guy on my friends' list to get to moo shu, he then invited all his lower level buddies to come meet him, and they all went and "farmed" a higher level boss with lower hit points. In numbers, the high level boss became easier for them to farm over and over for items that sold for a lot of gold. Then they'd go back to Wizard City and buy the lower level zeke clothes with the gold and become really powerful low level characters. I'm such an enabler . . . ;-)
Hope this helps, Sean!