If you’re going to give your eye teeth, it better be for something pretty darn valuable. The term eye tooth refers to the canine teeth in your upper jaw, called so because of their placement below the eyes. Giving up these teeth would not only be painful and impossible to disguise, but it might also suggest a loss of prestige or rank. In the 1700’s, “to cut your eye teeth” meant to have matured into adulthood. This is probably derived from the fact that the upper canine teeth on an actual canine are long and fang-like, and a dog would have the capacity to hunt or fight for itself once those teeth had grown in.