A super nerd word for "the guy taking all the damage in a mmorpg game" Think total dumbfuck that has no spell casting ability and can swing a giant axe so he moronically runs in front of everyone like a big tank.
Nerdwithnorealworldskills20008 is tanking! Hey put your hex spells on that him so we can mow him down with our +98 damage wind avenger blade spells! Pass the cheese wizz and graham crackers Bill!
In a classroom/graded setting, one relies on the current postitive status of their grade, using it as a buffer in hopes to get to the end of the grading period doing little or no work with mild to no consequence.
Similar to how a tank in an MMO can rely on buffs to stay alive in a mob, a mob being in this case either a class or a giant-ass homework load.
Tanking Comes from MMORPGs That run off a Kill = Exp Style not a Hit = Exp.
A much stronger player would be inclined to First hit a monster and let themselves take Damage, While a Much lower level Attacks and Kills it, (i.e Gaining all the exp)
Thinking in absolute isolation, without any visual or aural aids, influences or clues. Usually done in a special isolation tank, developed by John Lilly, where the tanker lies naked and alone for long periods of time. Such process might interest biologists, writers and psilosophers.
Watch KenRussell's film "Altered States" for a great take on the subject.