What does dipole mean?
A dipole is, at its simplest, a pair of equal and oppositely signed poles separated by a short distance — most commonly a pair of electric charges or magnetic poles. The word belongs primarily to the vocabulary of physics, chemistry, and engineering, where it describes fundamental structures: an electric dipole consists of a positive and a negative charge held close together, while a magnetic dipole behaves like a tiny bar magnet with north and south poles. Chemists use the related idea of a dipole moment to measure how unevenly charge is distributed across a molecule, which explains why substances like water dissolve salts so effectively while symmetric molecules like carbon dioxide do not. Engineers build dipole antennas, whose two conductive arms radiate and receive radio waves. Though technical, the concept underpins much of modern science, from molecular bonding to broadcast transmission.
nounA pair of equal and opposite electric charges or magnetic poles separated by a small distance; more broadly, any system with two such opposing poles. In physics and chemistry, the term also refers to a molecule or bond with separated positive and negative charge (a dipole moment).
- A pair of equal and opposite electric charges or magnetic poles separated by a distance, especially as treated in physics (an electric or magnetic dipole).
- A molecule or chemical bond having a separation of positive and negative charge, quantified by a dipole moment.
"A water molecule is a dipole, which is why it dissolves salts so readily."
"The radio transmitter fed its signal into a simple half-wave dipole strung between two trees."
"Because carbon dioxide is linear, its bond dipoles cancel and the molecule as a whole has no net dipole."
Regular English plural; standard in all varieties.
"The field pattern results from the interaction of many dipoles aligned within the material."
The humble dipole antenna — little more than two metal rods — carried the first radio signals across the Atlantic and still sits inside almost every wireless device you own.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dipole
Dipole was coined in the nineteenth century from Greek roots: "di-", meaning "two", combined with "polos" (πόλος), meaning "pole" or "axis", the same root that gives us "polar" and "polarity". It arose as physicists formalised the study of electricity and magnetism and needed a precise term for systems of paired opposing poles. Its relatives include other "di-" compounds borrowed directly from Greek, such as dioxide and diode.
How dipole is actually used
Dipole is a technical term used chiefly in physics, chemistry, and electrical engineering; in everyday speech it appears mainly in fixed phrases such as "dipole moment" or "dipole antenna." It is neutral in register but assumes some scientific literacy in the audience.
Easily confused with dipole
A diploma is a certificate awarded for completing a course of study, while a dipole is a physical pair of opposing electric charges or magnetic poles.