Bipolar

Bipolar refers to something of or relating to two poles or extremities, or having two poles. For example, earth is bipolar, because it has two poles - North Pole and South Pole. Anything relating to or occurring in both the polar regions is also called bipolar, such as bipolar species of living organisms. In electronics, a transistor or device that uses both the positive and negative charge carriers is called a bipolar transistor or device. This term is also used in psychology and psychiatry, for an illness in which patients suffer alternately from both maniac and depressive mental conditions. It may also be noted that some patients suffering from only maniac conditions are also called bipolar patients. In biology, this term is used for a nerve cell having two axons on both of its sides.