A Transition Zone is a physical area in which the properties, or the behaviour of something undergoes a radical change. (e.g., one formula is used at smaller values of the independent variable and another formula is used at larger values of the independent variable; a thin and very irregular layer of the Sun’s atmosphere that separates the hot corona from the much cooler chromosphere; a fluid flow in which the nature of the flow is changing from laminar to turbulent; A region within the upper mantle bordering the lower mantle, at a depth of 410-1000 kM; a region within the outer core, transitional to the inner core)

Related Definitions in the Project: The Property and Unit