Medium is the singular form of the plural form “media” but when referring to communication and information media, the proper collective term to use, whether in singular or plural form, is “the media.” Usually, technology-related information conduits such as radio and television encompass what media is, but art forms such as literature (in the form of books) and films are also considered as part of media.
When discussing media as the channel, especially in the typical SMCR communication model, these pertain to the specific media industry or creative industry that encompasses such a channel. These include the film industry, the broadcast industry (covering radio and television), the publishing industry (covering books, newspapers, magazines and comics), and the photography industry. Companies and telecommunications providers that make it possible for us to go online constitute the Internet industry. Although not an industry in itself like how the film or television industry is, the Internet could also be considered as a media channel. Various emerging and developing media-related technologies, especially those belonging in the information technology (or IT) sector such as mobile phones or tablets, could also be placed in this category of media channels. Whatever is used to deliver a media-constructed message becomes a media channel.
Viewing media in this manner, the concern of being a channel is to primarily disseminate information to a wide audience. That is why the development of early forms of media was directly connected to supporting or servicing other sectors in society, particularly in transportation (since information has to be physically delivered, like letters), the military and the government (communication exchange of classified information is crucial to military and political affairs), and also in journalism. This is also why, when we think of media, it is predominantly synonymous or attached to important information suppliers like newspapers.