Other forms: mass media
A technology that communicates information or entertainment to a large audience is a mass medium. Television and the internet are examples of mass media.
You'll most often find this phrase in its plural form, referring to the entire category of communications you use to learn about everything from current events to celebrity gossip. The mass part of Mass media comes from the vast number of people who watch, listen to, or read those sources. Your handwritten zines may be media, but their small audience means they're not mass media, unlike the New York Times and YouTube.