Merriam-Webster Collegiate Dictionary - bipolar

 adjective  Date: 1810  1. having or marked by two mutually repellent forces or diametrically opposed natures or views  2.  a. having or involving the use of two poles or polarities  b. relating to, being, or using a transistor in which both electrons and holes are utilized as charge carriers  3. relating to, associated with, or occurring in both polar regions ~ species of birds  4. being, characteristic of, or affected with a ~ disorder  • ~ity noun  • ~ization noun  • ~ize transitive verb