The Body (a.k.a. the Body of Consciousness) refers to the Physical Universe as a container for Consciousness. The phrase may refer to the entire physical universe as a container for Consciousness, an individual Physical Unit as a container for Monadic Consciousness, and all stops in between.
The Body is the lowest (in terms of vibratory frequencies) "level" of Creation. The Body is what you see when you open your eyes in a Physical Unit.
It is important to understand that Consciousness embraces and enters into The Body at all levels of aggregation, although the most varied, interesting, self aware, and useful expressions of consciousness occur within those aspects of The Body that are able to support full expression of Consciousness, i.e. bodies which can support life.