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me·di·um (mēdē-əm)
n. pl. me·di·a(-dē-ə) or me·di·ums
1. Something, such as an intermediate course of action, that occupies a position or represents a condition midway between extremes.
2. Physics
a. A substance that propagates energy or signals through space via changes in its own state: Air acts as a medium for the transmission of sound waves.
b. The sparsely distributed gas and dust subsisting in the space between stars.
3. An agency by which something is accomplished, conveyed, or transferred: The train was the usual medium of transportation in those days.
4. pl. media Usage Problem
a. A means of mass communication, such as newspapers, magazines, radio, or television.
b. media(used with a sing. or pl. verb) The group of journalists and others who constitute the communications industry and profession.
5. pl. media Computers Any of various kinds of storage devices, such as hard drives or digital audiotape.
6. pl. mediums A person thought to have the power to communicate with the spirits of the dead or with agents of another world or dimension. Also called psychic.
7. pl. media
a. A surrounding environment in which something functions and thrives.
b. The substance in which a specific organism lives and thrives.
c. A culture medium.
a. A specific kind of artistic technique or means of expression as determined by the materials used or the creative methods involved: the medium of lithography.
b. The materials used in a specific artistic technique: oils as a medium.
9. A solvent with which paint is thinned to the proper consistency.
10. Chemistry A filtering substance, such as filter paper.
Occurring or being between two degrees, amounts, or quantities; intermediate: ordered a medium coffee. See Synonyms at average.

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

Usage Note: Media was originally the plural of medium, though it has come to be used as a collective term for the press, entertainment industry, and other channels of mass communication. Whether to use a singular or plural verb with media depends on the intended meaning. If the point is to emphasize the multifaceted nature of the press, a plural verb is appropriate: The media have covered the trial in a variety of formats. When it refers to the entire aggregate, a singular verb is often used: The media has not shown much interest in covering the trial. Nonetheless, the Usage Panel has a decided preference for the plural use even with the aggregate sense, with 95 percent in 2017 accepting The media have covered the trial in a variety of formats and only 59 percent accepting the sentence The media has not shown much interest in covering the trial. Clearly, many people still perceive media as a plural, and it will be some time before the singular analysis crowds out the plural in the manner of similar Latin plurals such as agenda and candelabra. · The singular media is sometimes used to refer to a specific means of communication, but many writers frown on this usage: In our 2017 survey, 79 percent of the Usage Panel rejected the sentence The internet is the most exciting new media since television. In such a sentence, medium is the better option. But though medium is entirely standard when referring to a generic means of communication, such as print or television, it is somewhat nonstandard when referring to the particular institutions employing such a means, such as newspapers or television networks: while 62 percent of the Usage Panel accepted the sentence No medium has shown much interest in covering the trial in our 2017 ballot, several of the Panelists commented that although they accepted the sentence, they nonetheless found it “weird” or “strange.”

The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.

Indo-European & Semitic Roots Appendices

    Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:

    Indo-European Roots

    Semitic Roots

    The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.