tanking

comes from mmorpgs, where you would have a healer in your party and a person with high defense. (i.e. meat sack-o-shield warriors). the warrior rush an opponent and the monk would do their best to keep the warrior alive with healing and stat bonuses. then, the other members could a)fight and hit hard b)run away like scared little girls so, in essence, it is a big distraction to open opportunites for attack or to run away, like a sacrifice but to keepp it alive.