redcoat (n.)

"of a bright, warm color resembling that of blood or of the highest part of the primery rainbow" [Century Dictionary], Middle English rēd, redde, read, reid, from Old English rēad, used of various shades of purple, crimson, scarlet, pink, etc.; also red clothes, dye, ink, wine, or paint, also "having a ruddy or reddish complexion; red-haired, red-bearded;" from Proto-Germanic *rauthan (source also of Old Norse rauðr, Danish rød, Old Saxon rod, Old Frisian rad, Middle Dutch root, Dutch rood, German rot, Gothic rauþs).

This is reconstructed to be from a PIE root *reudh- "red, ruddy," the only color for which a definite common PIE root word has been found. It also is the root of native ruddy, rust, and, via Latin, ruby, rubric, russet, etc.

Along with dead, bread (n.), lead (n.1), its long vowel shortened in or after Middle English. The surname Read, Reid, Reade, etc. represents the old form of the adjective and retains the original Old English long vowel pronunciation. It corresponds to Brown, Black, White; Red itself being rare as a surname. As the color designation of Native Americans in English from 1580s.

In fixed comparisons, red as blood (Old English), roses (mid-13c.), cherry (c. 1400). From Old English as the color characteristic of inflammation, blistering, etc. Of the complexion, lips, etc., "ruddy, rosy, red" (c. 1200); also of person with a healthy complexion or skin color; to be red in the face as a result of powerful emotion or agitation is by c. 1200; to see red "get angry" is an American English expression attested by 1898.

Red as the characteristic color of "British possessions" on a map is attested from 1885. Red-white-and-blue in reference to American patriotism, from the colors of the flag, is from 1840; in a British context, in reference to the Union flag, 1852.

Red rover, the children's game, attested from 1891. Red ball signifying "express" in railroad jargon is by 1904, originally (1899) a system of moving and tracking freight cars. Red dog, type of U.S. football pass rush, is recorded from 1959 (earlier "lowest grade of flour produced in a mill," by 1889). Red meat, that which is ordinarily served or preferred undercooked, is from 1808; the food of wild beasts, hence its figurative use for something that satisfies a basic appetite (by 1792; popular from late 20c.).

Red shift in spectography is first recorded 1923. Red carpet "sumptuous welcome" is from 1934, but the custom for dignitaries is described as far back as Aeschylus ("Agamemnon"); it also was the name of a type of English moth. Red ant is from 1660s.

early 14c., "principal outer garment, tunic, kirtle," typically made of cloth and usually with sleeves, worn alone or under a mantle, from Old French cote "coat, robe, tunic, overgarment," from Frankish *kotta "coarse cloth" or some other Germanic source (compare Old Saxon kot "woolen mantle," Old High German chozza "cloak of coarse wool," German Kotze "a coarse coat"); the ultimate origin is unknown.  Spanish, Portuguese cota, Italian cotta are Germanic loan-words.

Coats of modern form, fitted to the body and having loose skirts, first appeared in the reign of Charles II of England. Since the beginning of the eighteenth century the coat has been of two general fashions: a broad-skirted coat, now reduced to the form of the frock-coat ..., and a coat with the skirts cut away at the sides (the modern dress coat), worn now only as a part of what is called evening dress. [Century Dictionary, 1897]

As "garment worn suspended from the waist by women and children" from late 14c. (the sense in petticoat). Transferred late 14c. to "the natural external covering of an animal." Extended 1660s to "a thin layer of any substance covering any surface." Coat-hanger "clothes-hanger designed to facilitate the hanging of a coat" is from 1872. Coat-card (1560s) was any playing card which has a figure on it (compare face-card). It later was corrupted to court-card(1640s).