There are several words with Latin or Greek roots whose plural forms ending in A are constantly mistaken for singular ones. See, for instance, criteria and data. Radio is a broadcast medium. Television is another broadcast medium. Newspapers are a print medium. Together they are media.
Following the tendency of Americans to abbreviate phrases, with “transistor radio” becoming “transistor,” (now fortunately obsolete) and “videotape” becoming “video,” “news media” and “communications media” have been abbreviated to “media.”
Remember that watercolor on paper and oil on black velvet are also media, though they have nothing to do with the news. When you want to get a message from your late Uncle Fred, you may consult a medium. The word means a vehicle between some source of information and the recipient of it. The “media” are the transmitters of the news; they are not the news itself.
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