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

  • adj. Impossible or difficult to perceive by the mind or senses: an imperceptible drop in temperature.
  • adj. So subtle, slight, or gradual as to be barely perceptible: an imperceptible nod.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. Not perceptible, not detectable, too small in magnitude to be observed.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Not perceptible; not to be apprehended or cognized by the senses; not discernible by the mind; not easily apprehended.

from The Century Dictionary and Cyclopedia

  • Not perceptible; that cannot be perceived.
  • Incapable by nature of affecting the senses.
  • Too minute, fine, gradual, subtle, or evanescent to be discerned by the senses; producing an excitation of the nerves less than the threshold of sensation. See threshold.
  • n. That which cannot be perceived with the naked eye, or realized by sensation.

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

  • adj. impossible or difficult to perceive by the mind or senses


from Wiktionary, Creative Commons Attribution/Share-Alike License

Middle English, from Middle French, from Medieval Latin imperceptibilis


  • My brother rose to do so but he saw neither ewer nor basin; yet his host kept washing his hands with invisible soap in imperceptible water and cried,

    The Book of The Thousand Nights And A Night

  • But [since without water tasting is impossible] either (a) we must suppose that water contains in itself [uniformly diffused through it] the various kinds of savour, already formed, though in amounts so small as to be imperceptible, which is the doctrine of

    On Sense and the Sensible

  • For what is called imperceptible and incomprehensible does not produce an impression, because it is not a real fact, but a concept: the requisite of bulk in the beautiful is thus reduced to the effective reality of the physical fact, which serves for the reproduction of the beautiful.

    Aesthetic as Science of Expression and General Linguistic

  • He particularly praised an initiative to reduce salt levels by encouraging manufacturers to decrease levels by tiny "imperceptible" amounts at a time? which added up to large reductions over many years.

    Andrew Lansley to cut thousands of jobs in purge of NHS 'bureaucracy'

  • But these efforts have been repeatedly blocked by Republicans and fiercely opposed by oil lobbyists, who, among other things, argue it will increase the cost of oil (Greenstone says the impact on a global industry like oil would be "imperceptible").

    Chris Kromm: Outdated Law Gives Oil Companies Incentives to Spill

  • The team says any noise from the concept aircraft, known as the SAX-40, would be "imperceptible" beyond the boundaries of an airport.

    Archive 2006-11-01

  • The origin of the that 'imperceptible' time compression sometimes used on cable is mentioned briefly.

    The Media Lab by Stewart Brand

  • Medialive's unique combination of content protection and content identification allows: controlling content distribution, providing content owners with technical means to dissuade digital piracy and improving the user experience (being "imperceptible" to consumers) while being interoperable with existing DRM / CAS and tracking systems.

    Help Net Security - News

  • Yet we begin by emphasizing that some things never change or at any rate change so slowly as to be virtually imperceptible.

    American Grace

  • When he was sorry about me, sorry for coming to Prague, sorry for ever sleeping with me in the first place, he liked to use my full name as an imperceptible method of scolding.

    The Adults


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