penumbra
Pronunciation:
/pəˈnʌmbɹə/noun
Definitions
A partially shaded area around the edges of a shadow, especially an eclipse.
A region around the edge of a sunspot, darker than the sun's surface but lighter than the middle of the sunspot.
An area of uncertainty or intermediacy between two mutually exclusive states or categories.
An area that lies on the edge of something; a fringe.