Green’s Dictionary of Slang

shade n.1

[SE shade, partial darkness]

1. [mid-18C] (UK Und.) a wig.

2. [mid-19C] (US Und.) an umbrella or sunshade.

3. [mid–late 19C] in pl., a variety of late-night music-halls and bars on or near the Strand, London; used generically in US [their opening during the ‘shady’ hours].

4. in racial contexts.

(a) [mid-19C–1960s] (US) a derog. term for a black person.

(b) [1960s+] (US) a derog. term for a white person; occas. as adj.

5. [1920s+] (US Und.) a receiver of stolen goods.

6. [1930s+] (Irish) a police officer.

7. [1950s+] in pl., dark glasses, sunglasses [note 19C shades, goggles, e.g. for use during stone-breaking].

In phrases

in the shade

[1910s-20s] (US Und.) in prison.