What does electret mean?
An electret is a piece of insulating (dielectric) material that has been given a quasi-permanent electric charge or polarization — meaning it retains its internal electric state for years or even decades without needing any external power supply. It occupies the same conceptual role in electrostatics that a permanent magnet plays in magnetism: just as a magnet sustains a magnetic field on its own, an electret sustains an electrostatic one. The word was introduced by the British physicist Oliver Heaviside in the late nineteenth century as a deliberate blend of 'electric' and 'magnet'. Although electrets remained largely laboratory curiosities for decades, they became commercially important in the twentieth century, most famously as the polarizing element in electret condenser microphones, which are now standard in phones, laptops, and hearing aids. They also appear in electrostatic air filters and certain types of radiation dosimeters. The term is technical rather than colloquial, but it describes a component quietly embedded in everyday technology.
nounA dielectric material that exhibits a quasi-permanent electric charge or polarization, retaining it for long periods without an external power source. It is the electrostatic analogue of a permanent magnet.
- A dielectric material with a quasi-permanent electric charge or polarization, used in devices such as microphones, air filters, and radiation dosimeters.
"The microphone in the hearing aid relies on an electret to convert sound waves into electrical signals."
"Because an electret holds its charge indefinitely without external power, it became the heart of the modern condenser microphone."
"Researchers tested the electret film for use in energy-harvesting devices that capture ambient vibration."
Regular plural; used when referring to multiple such materials or devices.
"Thin polymer electrets are widely used in commercial microphones."
Coined by blending 'electric' and 'magnet', the electret is essentially electricity's answer to the fridge magnet — and it's hiding inside nearly every microphone you own.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of electret
The word 'electret' was coined by the self-taught British physicist Oliver Heaviside in 1885, formed by blending 'electric(al)' with the ending of 'magnet' — a naming choice meant to signal that the electret stands to electric charge what the magnet stands to magnetism. The root 'electric' itself traces back through New Latin 'electricus' ('of amber') to Greek 'ēlektron', meaning amber, the substance whose static attraction first drew attention to electricity. Cognates sharing this Greek lineage include 'electron' and 'electrify'.
How electret is actually used
Strictly technical vocabulary, found mainly in physics, materials science, and electronics contexts. Rarely encountered outside specialist literature, though the term appears in consumer product descriptions of microphones.
Easily confused with electret
A magnet produces a permanent magnetic field, whereas an electret is the analogous dielectric that carries a quasi-permanent electric polarization.