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

  • n. The principal spring in a mechanical device, especially a watch or clock, that drives the mechanism by uncoiling.
  • n. The chief motivating force: the mainspring of a reform movement.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The principal spring of a clockwork mechanism, that drives it by uncoiling.
  • n. The most important reason for something.

from the GNU version of the Collaborative International Dictionary of English

  • n. The principal or most important spring in a piece of mechanism, especially the moving spring of a watch or clock or the spring in a gunlock which impels the hammer.

from The Century Dictionary and Cyclopedia

  • n. The principal spring of any piece of mechanism, as, in a gun-lock, the spring which operates the hammer; specifically, the coiled spring of a watch or other timepiece.
  • n.
  • n. The impelling cause of any action; the inciting motive.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. the most important spring in a mechanical device (especially a clock or watch); as it uncoils it drives the mechanism


Sorry, no etymologies found.


  • When the spiritual stage of her evolution is reached, this occult process must become the whole process; to get through the veil of forces and get at their secret mainspring, which is the Spirit itself, is of cardinal importance.

    Archive 2007-10-01

  • Journalism of which the mainspring is the gaining of pleasure may easily degenerate into something akin to the comic actor's function.

    The Adventure of Living

  • The teacher who can break a mainspring first and keep it from getting mended, is often the most esteemed in the community.

    The Lost Art of Reading

  • Our "mainspring" not only has run down, but is broken.

    Diary of the Besieged Resident in Paris

  • "The system of which you have been speaking might be called the mainspring of our society.

    Daybreak; a Romance of an Old World

  • Referring to Orme, Shirley sniffed, “It is a joke to suppose that secondary officers can make amends for the defects of the first; the mainspring must be the mover—the others in many cases can do no more than follow and correct a little its motions.”

    George Washington’s First War

  • That this dog and White Fang should come together was inevitable, and for a week the anticipated fight was the mainspring of conversation in certain quarters of the town.

    Reign of Hate

  • For instance, say your mainspring event was a fatal car accident.

    Writer Unboxed » Blog Archive » Not losing the plot

  • We want to uncover the mainspring for mass murder.


  • If Hethor fails to wind the mainspring before a given date, the world ends.

    Under Deconstruction


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