Definition for Establishing shot
From Biology Forums Dictionary
1) sets the scene or shows the space of a scene; often a long shot or series.
2) (a.k.a. "Master Shot") At the beginning of a film, episode or scene within a film, a wide-angle or "full-shot" is photographed for the purpose of identifying the location or setting. Thus the audience has established, or been given the opportunity to surmise an orientation. It also helps to establish the distinctions between the general locale and the specific details -- from subsequent shots -- within the general context. [The Establishing shot is a wide-angle shot and/or a long shot.]