Shade is the blocking of sunlight (in particular direct sunshine) by any object. It may refer to blocking of sunlight by a roof, or by a tree, by an umbrella, or anything else.
Shade is an important issue in temperate and tropical zones for providing cooling and shelter from the sun. Providing certain configurations of shading is an important passive solar technique. This may be done with overhangs, with shade trees, or with vines.
Shading using non-living materials blocks the sun, but also results in sunlight being absorbed and re-radiated as heat, or in sunlight being reflected as glare. Green plants, on the other hand, not only absorb a significant portion of the sunlight to invest as energy in photosynthesis to produce sugar, but also actively transpire, producing an additional cooling effect.
Shading is also a process used in drawing for depicting different levels of blackness on paper by applying more pressure of the pencil for darker areas and less pressure for lighter areas. There are various techniques of shading including 'cross hatching' where perpendicular lines of varying closeness are drawn in a grid pattern in the area you wish to shade. The closer the lines are together, the darker the area will appear and vice versa.
See also Shadow.