black (n.)youdaoicibaDictYouDict
Old English blæc "the color black," also "ink," from noun use of black (adj.). From late 14c. as "dark spot in the pupil of the eye." The meaning "black person, African" is from 1620s (perhaps late 13c., and blackamoor is from 1540s). To be in the black (1922) is from the accounting practice of recording credits and balances in black ink.
For years it has been a common practice to use red ink instead of black in showing a loss or deficit on corporate books, but not until the heavy losses of 1921 did the contrast in colors come to have a widely understood meaning. ["Saturday Evening Post," July 22, 1922]
blackout (n.)youdaoicibaDictYouDict
also black-out, 1908 in the theatrical sense of a darkened stage, from black + out. Figurative sense of "loss of memory" is 1934 (verb and noun); as a dousing of lights as an air raid precaution, it is recorded from 1935. Verbal phrase black out, in reference to printed or written matter deemed objectionable and covered in black ink, is attested from 1888.
nigger (n.)youdaoicibaDictYouDict
1786, earlier neger (1568, Scottish and northern England dialect), from French nègre, from Spanish negro (see Negro). From the earliest usage it was "the term that carries with it all the obloquy and contempt and rejection which whites have inflicted on blacks" [cited in Gowers, 1965, probably Harold R. Isaacs]. But as black inferiority was at one time a near universal assumption in English-speaking lands, the word in some cases could be used without deliberate insult. More sympathetic writers late 18c. and early 19c. seem to have used black (n.) and, after the American Civil War, colored person.
"You're a fool nigger, and the worst day's work Pa ever did was to buy you," said Scarlett slowly. ... There, she thought, I've said "nigger" and Mother wouldn't like that at all. [Margaret Mitchell, "Gone With the Wind," 1936]
Also applied by English settlers to dark-skinned native peoples in India, Australia, Polynesia. The reclamation of the word as a neutral or positive term in black culture (not universally regarded as a worthwhile enterprise), often with a suggestion of "soul" or "style," is attested first in the U.S. South, later (1968) in the Northern, urban-based Black Power movement.

Used in combinations (such as nigger-brown) since 1840s for various dark brown or black hues or objects; euphemistic substitutions (such as Zulu) began to appear in these senses c. 1917. Brazil nuts were called nigger toes by 1896. Variant niggah, attested from 1925 (without the -h, from 1969), is found usually in situations where blacks use the word. Nigra (1944), on the other hand, in certain uses reflects a pronunciation of negro meant to suggest nigger, and is thus deemed (according to a 1960 slang dictionary) "even more derog[atory] than 'nigger.' " Slang phrase nigger in the woodpile attested by 1800; "A mode of accounting for the disappearance of fuel; an unsolved mystery" [R.H. Thornton, "American Glossary," 1912]. Nigger heaven "the top gallery in a (segregated) theater" first attested 1878 in reference to Troy, N.Y.