Action potential: why called "depolarization" when polarity is reversed, not removed?
While the cell is polarized (in the positive direction) at the height of the action potential, it has been depolarized from its resting, negatively charged state, meaning the original polarity has been lost or reversed. In my mind, the slight (30mV max) positive polarization for that brief period of time is kind of an "overshoot" of neutral charge, just like during recovery the potential exceeds -70mV for a period of time before coming back to the resting state.