A term used to describe different levels of reality, moving from the most tangible physical plane to the most intangible etheric levels. Because these different levels or planes are often pictured as forming a hierarchic or ladder-like structure, this sometimes leads to the inaccurate interpretation of the planes as being separate and on top of each other. In fact, they interpenetrate. Theosophists do see separate layers, but ones that gradually blend into each other rather than having hard separations.