from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A solid dielectric that exhibits persistent dielectric polarization.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun physics a solid dielectric having a quasi-permanent charge; usually a metallized film; used in electroacoustic and electromechanical transducers and in air filters


from The American Heritage® Dictionary of the English Language, 4th Edition

[electr(icity) + (magn)et.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

Blend of electricity and magnet.



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  • Term coined in 1885 by Oliver Heaviside. An electret is the electrostatic equivalent of a permanent magnet.

    August 4, 2009

  • Heaviside? What a delightful name.

    August 4, 2009

  • Why I love Wordie, reason #817:

    I was just about to leave a comment on this page, involving a lame pun on the coincidental similarity between the name "Oliver Heaviside" and the "Heaviside Layer" (from the musical Cats), but first I googled "Heaviside Layer", and discovered, to my shock and delight, that there actually is a Heaviside Layer. It's part of Earth's ionosphere, and it was named after our man Oliver. T.S. Eliot just borrowed the term to describe his mystical feline heaven.

    Wikipedia also gives the following interesting information (without any citations to support it):

    "In later years... Heaviside would sign letters with the initials "W.O.R.M." after his name though the letters did not stand for anything. Heaviside also reportedly started painting his fingernails pink and had granite blocks moved into his house for furniture."


    August 4, 2009

  • I vaguely remember being exposed to something called the Heaviside function in my applied mathematics class, lo these many years ago. IIRC it had the odd property of being either right or left continuous, but not totally continuous.

    Had I known about the pink fingernails and granite furniture, obviously I would have paid much closer attention.

    Add this page to my reasons for lurving Wordie with a mad passionate lurve.

    August 4, 2009