1. (information source) In Shannon and Weaver's model, the point of origin of a message. For example, in speech communication, the source would be the speaker (see also author; source factors).
2. In the mass media, the perceived origin of a message. In advertisements, where a model or actor is a spokesperson for the product in the ad, they count as a source: compare sender.
3. A person from whom a journalist obtains information for a news story. The mass media are often criticized for over-reliance on official sources.
4. In linear editing, the playback as opposed to the ‘record’ machine.