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

  • noun Something, such as an intermediate course of action, that occupies a position or represents a condition midway between extremes.
  • noun An intervening substance through which something else is transmitted or carried on.
  • noun An agency by which something is accomplished, conveyed, or transferred.
  • noun A means of mass communication, such as newspapers, magazines, radio, or television.
  • noun The group of journalists and others who constitute the communications industry and profession.
  • noun Computers Any of various kinds of storage devices, such as hard drives or digital audiotape.
  • noun A person thought to have the power to communicate with the spirits of the dead or with agents of another world or dimension.
  • noun A surrounding environment in which something functions and thrives.
  • noun The substance in which a specific organism lives and thrives.
  • noun A culture medium.
  • noun A specific kind of artistic technique or means of expression as determined by the materials used or the creative methods involved.
  • noun The materials used in a specific artistic technique.
  • noun A solvent with which paint is thinned to the proper consistency.
  • noun Chemistry A filtering substance, such as filter paper.
  • noun A size of paper, usually 18 by 23 inches or 17.5 by 22 inches.
  • adjective Occurring or being between two degrees, amounts, or quantities; intermediate: synonym: average.

from The Century Dictionary.

  • noun That which holds a middle place or position; that which comes or stands between the extremes in a series, as of things, principles, ideas, circumstances, etc.; a mean.
  • noun Technically— In mathematics, a mean. See mean.
  • noun In logic, the mean or middle term of a syllogism.
  • noun A size of paper between demy and royal. American printing-medium is 19 × 24 inches; American writing-medium, 18 × 23 inches; English printing-medium, 18 × 28 inches; English writing-medium, 17½ × 22 inches; American double medium, 24 × 38 inches; and American medium and a half, 24 × 30 inches.
  • noun Anything which serves or acts intermediately; something by means of which an action is performed or an effect produced; an intervening agency or instrumentality: as, the atmosphere is a medium of sound.
  • noun Specifically— In painting, any liquid vehicle, as linseed-oil, poppy-oil, varnish, or water, with which dry pigments are ground, or with which pigments are mixed by the painter while at work, in order to give them greater fluidity.
  • noun In acoustics, a ponderable elastic substance, as air or other gas, water, etc., which transmits the energy of the sounding body in waves of condensation and rarefaction to the ear.
  • noun In heat and light, that which transmits the energy of the heated or luminous body to a distance in undulatory waves; the ether.
  • noun In bacteriology, the nutritive substance, either a liquid or a solid, in which or upon which the various forms of microscopic life are grown for study. The liquid media employed are infusions of hay, extract of beer-yeast, and broth of various kinds of meat. The solid media most used are eggs, slices of potatoes and carrots, agar-agar, and especially gelatin and the gelatinized serum of the blood of oxen. After being thoroughly sterilized by heat, they are usually placed in test-tubes, and inoculated with the form that it is desired to study; the cultures may then be observed through the glass.
  • noun A person through whom, or through whose agency, another acts; specifically, one who is supposed to be controlled in speech and action by the will of another person or a disembodied being, as in animal magnetism and spiritualism; an instrument for the manifestation of another personality.
  • noun Something of mean or medium weight, size, etc.
  • Middle; middling; mean: as, a man of medium size.

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

  • adjective Having a middle position or degree; mean; intermediate; medial
  • noun That which lies in the middle, or between other things; intervening body or quantity.
  • noun Middle place or degree; mean.
  • noun (Math.) See Mean.
  • noun (Logic) The mean or middle term of a syllogism; that by which the extremes are brought into connection.
  • noun A substance through which an effect is transmitted from one thing to another.
  • noun rare An average.
  • noun A trade name for printing and writing paper of certain sizes. See Paper.
  • noun (Paint.) The liquid vehicle with which dry colors are ground and prepared for application.
  • noun (Microbiology) A source of nutrients in which a microorganism is placed to permit its growth, cause it to produce substances, or observe its activity under defined conditions; also called culture medium or growth medium. The medium is usually a solution of nutrients in water, or a similar solution solidified with gelatin or agar.
  • noun A means of transmission of news, advertising, or other messages from an information source to the public, also called a news medium, such as a newspaper or radio; used mostly in the plural form, i. e. news media or media. See 1st media{2}.
  • noun a current medium of exchange, whether coin, bank notes, or government notes.
  • noun (Physics) the ether.
  • noun that which is used for effecting an exchange of commodities -- money or current representatives of money.

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

  • noun The nature of the surrounding environment, e.g. solid, liquid, gas, vacuum, or a specific substance such as a solvent.
  • noun The material or empty space through which signals, waves or forces pass.
  • noun A format for communicating or presenting information.
  • noun engineering The materials used to finish a workpiece using a mass finishing or abrasive blasting process.
  • noun microbiology A nutrient solution for the growth of cells in vitro.


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

[Latin, from neuter of medius, middle; see medhyo- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Latin medium, neuter of medius ("middle"). Compare middle.


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  • Mag. _ in May 1861, writes: "I have deduced from this result the relation between statical or dynamical electricity, and have shown that the elasticity of the magnetic medium in air is the same as that of the luminiferous medium, _if these two coexistent, coextensive, and equally elastic media are not rather one medium_."

    Aether and Gravitation William George Hooper

  • Very good depth, but a bit closed up right now taste: delicious and smooth medium feel with excellent medium+ acidity and balanced tones of white fruits, pears, apples, apricots and a bit of nectarines.

    CellarTracker Tasting Notes (all notes) 2010

  • I sat down and ordered hot-and-sour soup (medium hot) and kung pao chicken (medium*).

    Wanderings and Maunderings georgmi 2010

  • Short finish upon opening, but with time medium to medium+ with airtime (and touch of drying tannins noticeable on the finish).

    CellarTracker Tasting Notes (all notes) 2010

  • In Latin textbooks of history the term medium aevum had existed for more than a century; Hornius had made it a subdivision of historia nova (moderna), and Cel - larius had presented his Historia universalis as in antiquam et medii aevi ac novam divisa (Jena, 1696).


  • The critic often uses the term medium as if it necessarily meant a professional, whereas every investigator has found some of his best results among amateurs.

    The Vital Message 1919

  • Scholastics comprise under the term medium rationis.

    The Catholic Encyclopedia, Volume 12: Philip II-Reuss 1840-1916 1913

  • The critic often uses the term medium as if it necessarily meant a professional, whereas every investigator has found some of his best results among amateurs.

    The Vital Message Arthur Conan Doyle 1894

  • To apply to it the distinguishing term medium, therefore, is positively misleading, since the smaller variety of red clover commonly grown occupies such middle ground, as the term medium would indicate.

    Clovers and How to Grow Them Thomas Shaw 1880

  • The term medium has doubtless come to be applied to it because the plants are in size intermediate between the Mammoth variety (_Trifolium magnum_) and the smaller varieties, as the Alsike (_Trifolium hybridum_) and the small white (_Trifolium repens_).

    Clovers and How to Grow Them Thomas Shaw 1880


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  • In my household, we refer to our cat this way. To differentiate from ourselves who are the "larges", and the "smalls" which are the the pocket-pets (rodents). A feral house-mouse is, then, similarly small, little or, better tiny; and insects are tiny or wee. If we had a ferret, I suspect it would be smallish or not-quite-medium]

    December 15, 2006

  • And your pet giraffe?

    October 24, 2008