Middle English schade, Kentish ssed, from late Old English scead "partial darkness; shelter, protection," also partly from sceadu "shade, shadow, darkness; shady place, arbor, protection from glare or heat," both from Proto-Germanic *skadwaz (cf. Old Saxon skado, Middle Dutch scade, Dutch schaduw, Old High German scato, German Schatten, Gothic skadus), from PIE *skot-wo-, from root *skot- "dark, shade" (cf. Greek skotos "darkness, gloom," Albanian kot "darkness," Old Irish scath, Old Welsh scod, Breton squeut "darkness," Gaelic sgath "shade, shadow, shelter").
Figurative use in reference to comparative obscurity is from 1640s. Meaning "a ghost" is from 1610s; dramatic (or mock-dramatic) expression "shades of _____" to invoke or acknowledge a memory is from 1818, from the "ghost" sense. Meaning "lamp cover" is from 1780. Sense of "window blind" first recorded 1845. Meaning "cover to protect the eyes" is from 1801. Meaning "grade of color" first recorded 1680s; that of "degree or gradiation of darkness in a color" is from 1680s (cf. nuance, from French nue "cloud"). Meaning "small amount or degree" is from 1782.
c.1400, "to screen from light or heat," from shade (n.). From 1520s as "to cast a shadow over;" figurative use in this sense from 1580s. Sense in painting and drawing is from 1797. In reference to colors, 1819. Related: Shaded; shading.
To defeat by a narrow margin: Michigan shaded Iowa. The final score was 98 to 96 (1865+)