The term media is an overloaded one when talking about the web; it takes on different meanings depending on the context.

Media (Audio-visual presentation)
The term media (more accurately, multimedia) refers to audio, video, or combined audio-visual material such as music, recorded speech, movies, TV shows, or any other form of content that is presented over a period of time.
Media (CSS)
In the context of CSS (Cascading Style Sheets), the term media refers to the destination to which the document is to be drawn by the rendering engine.

See also