noun
( -s )
1. : a covering or sheltering with shade : protection from heat or light
2. : the filling up within outlines that represents the effect of more or less darkness in a picture or a drawing
3. : a slight variation (as in color, quality, or class) : qualification
4. : a musical effect gained by subtle changes in dynamics as effected by the player
5. : a process of compensating for unwanted signals in a television picture caused by the scanning process especially during the trace interval or by inherent characteristics of the picture tube