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

  • adjective Equal in force, power, effectiveness, or significance.
  • adjective Logic Validly derived from each other; deducible.
  • adjective Equivalent.
  • noun An equivalent.

from The Century Dictionary.

  • Having equal power or force; equivalent.
  • In logic, having the same meaning: applied to two propositions.
  • In mathematics, equal and parallel.

from the GNU version of the Collaborative International Dictionary of English.

  • adjective Having equal power or force; equivalent.
  • adjective (Logic) Having equivalent signification and reach; expressing the same thing, but differently.

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

  • adjective having equal power or force
  • adjective logic able to be deduced from the other
  • adjective equivalent


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

[Middle English, from Old French, from Latin aequipollēns, aequipollent- : aequi-, equi- + pollēns, present participle of pollēre, to be powerful.]


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  • An equipollent system is kinda like an equivalent system except it doesn't adhere to the rigid body principle (the body has some flex mechanism or is not rigid).

    One of those words that don't seem like they really would exist but here it is anyways.

    October 2, 2008

  • A teen in the morning is indolent;

    The nocturnal beast’s still somnolent.

    The breakfast convention

    Will hang in suspension

    While hunger with sleep’s equipollent.

    February 17, 2018