media / medium
The plural, the mass noun, and agreement.
Medium is singular: Radio is a medium. Media is the plural. When media means the press as one body, it takes a singular verb: The media is covering the trial. When media means more than one medium, it takes a plural verb: The storage media are paper files and hard drives. Never write a media. One channel is a medium.
Examples
UseTelevision is a powerful medium. (one channel of communication)
UseThe media is camped outside the courthouse. (the press as one body)
UseThe storage media are paper files and hard drives. (two separate kinds of medium)
AvoidTikTok is a media for short videos. (one channel is a medium)