- A type of antenna made up of two active elements. Source: Church Audio & Acoustics Glossary
- An open-back speaker that radiates sound equally front and rear. The front and rear waves are out of phase and cancellation will occur when the wavelengths are long enough to "wrap around". The answer is a large, wide baffle or to enclose the driver creating a monopole. Source: http://www.owenscorning.com/around/sound/glossary.asp
- (chemistry) Refers to the separation of charge between two covalently bonded atoms.