Theoretically, a recognized member of the modern state system possessing formal sovereignty and occupied by a people who see themselves as a single, united nation. Most nations and states aspire to parlance, nation-state is used as a synonym for country or state.
In biology, depolarization is a decrease in the absolute value of a cell's membrane potential. Thus, changes in membrane voltage in which the membrane potential becomes less positive or less negative are both depolarizations.
In the depolarized state, the inside of the cell becomes the positive pole and the outside of the cell becomes the negative pole. The increase in membrane potential created between the inside and the outside of the cell during depolarization is called the action potential. Once a cell is excited (depolarized), it can excite adjacent cells and pass on its action potential, spreading depolarization to more and more cells.