Mass media are media like radio, television, internet or other things that reach many people. Television is most used. We can see and hear news from around the world. Radio also brings music and news. Books supply older and more detailed material. The internet is also important. We can search for all the news and information. Websites like Wikipedia and about.com give information about many things. Libraries are also important. In libraries we can read books and listen to music.
The term was coined in the 1920s with the advent of nationwide radio networks, mass-circulation newspapers and magazines, although mass media (like books and manuscripts) were present centuries before the term became common.
Mass media for Kids. Kiddle Encyclopedia.