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

  • Below; beneath; under: hypodermic.
  • Less than normal; deficient: hypoesthesia.
  • In the lowest state of oxidation: hypoxanthine.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • Below; beneath; under.
  • Deficient; less than normal.
  • A name for oxoacid and oxyanions with a low amount of oxygen.

from the GNU version of the Collaborative International Dictionary of English

  • A prefix signifying a less quantity, or a low state or degree, of that denoted by the word with which it is joined, or position under or beneath.
  • A prefix denoting that the element to the name of which it is prefixed enters with a low valence, or in a low state of oxidization, usually the lowest, into the compounds indicated.


Greek hupo-, from hupo, under, beneath; see upo in Indo-European roots.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek ὑπο- (hypo-), combining form of ὑπό (hypó, "under"). Compare sub-. (Wiktionary)


  • You also may experience hypo- or hyper-pigmentation, where patches of your skin may appear lighter or darker than surrounding areas.

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  • Some scars present as post-inflammatory hypo- or hyperpigmentation PIH.

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  • Dark skin types (Fitzpatrick Types 5 and 6) should stay away from IPL and pigment-targeting lasers such as the Nd:YAG, since they can cause postinflammatory hypo- or hyperpigmentation (PIH).

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  • Darker skin and Asian complexions Fitzpatrick Types 3 to 6 are prone to ill effects—primarily postinflammatory hypo- or hyperpigmentation or PIH—from stronger peels, especially melanotoxic TCA.

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  • The location below the center of a nuclear detonation is, strictly speaking, the hypocenter, with the Greek hypo- meaning “under”; that word was soon overtaken by epicenter the Greek prefix epi- means “on, over”, the outbreaking point on the earth’s surface above the focus of an earthquake.

    The Right Word in the Right Place at the Right Time

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