shade 
(shād)
(shād)n.
1. Light diminished in intensity as a result of the interception of the rays; partial darkness.
2. Cover or shelter provided by interception by an object of the sun or its rays: sat in the shade under the tree.
3. The part of a picture or photograph depicting darkness or shadow.
4.
a. A gradation of a color as it is mixed with black or is decreasingly illuminated: shades of gray.
b. A slight difference or variation; a nuance: shades of meaning. See Synonyms at nuance.
c. A small amount; a trace: detected a shade of bitterness in her remarks.
5.
a. Any of various devices used to reduce or screen light or heat: closed the window shades.
b. shades Informal Sunglasses.
6. shades
a. Dark shadows gathering at dusk: "The shades of night are falling fast" (Henry Wadsworth Longfellow).
b. The abode of the dead; the underworld: went to the shades of hell.
7.
a. A disembodied spirit; a ghost.
b. shades A present reminder of a person or situation in the past: shades of my high-school days.
v. shad·ed, shad·ing, shades
v.tr.
1. To screen from light or heat: Trees shaded the street.
2. To obscure or darken: "A sliver of mustache shaded his upper lip" (Michael Finkel).
3.
a. To represent degrees of shade or shadow in: shade a drawing.
b. To produce (gradations of light or color) in a drawing or picture: shaded the pink in the sunset.
4. To change or vary by slight degrees: shade the meaning.
5. To make a slight reduction in: shade prices.
v.intr.
Idiom: To pass from one quality, color, or thing to another by very slight changes or degrees.
a shade
A little bit; slightly: a sprinter who was a shade quicker that the rest.
[Middle English, from Old English sceadu.]
shader n.