blue-chip adj.

"of the color of the clear sky," c. 1300, bleu, blwe, etc., "sky-colored," also "livid, lead-colored," from Old French blo, bleu "pale, pallid, wan, light-colored; blond; discolored; blue, blue-gray," from Frankish *blao or some other Germanic source, from Proto-Germanic *blæwaz (source also of Old English blaw, Old Saxon and Old High German blao, Danish blaa, Swedish blå, Old Frisian blau, Middle Dutch bla, Dutch blauw, German blau "blue").

This is from PIE *bhle-was "light-colored, blue, blond, yellow," from root *bhel- (1) "to shine, flash, burn," also "shining white" and forming words for bright colors. The same PIE root yielded Latin flavus "yellow," Old Spanish blavo "yellowish-gray," Greek phalos "white," Welsh blawr "gray," showing the slipperiness of definition in Indo-European color-words. Many Indo-European languages seem to have had a word to describe the color of the sea, encompassing blue and green and gray; such as Irish glass (from PIE root *ghel- (2) "to shine,"); Old English hæwen "blue, gray," related to har (see hoar); Serbo-Croatian sinji "gray-blue, sea-green;" Lithuanian šyvas, Russian sivyj "gray."

The exact color to which the Gmc. term applies varies in the older dialects; M.H.G. bla is also 'yellow,' whereas the Scandinavian words may refer esp. to a deep, swarthy black, e.g. O.N. blamaðr, N.Icel. blamaður 'Negro' [Buck] 

The present spelling in English is since 16c., common from c. 1700. The sense "lead-colored, blackish-blue, darkened as if by bruising" is perhaps by way of the Old Norse cognate bla "livid, lead-colored." It is the meaning in black and blue, and blue in the face "livid with effort" (1864, earlier black and blue in the face, 1829).

The color of constancy since Chaucer at least, but apparently for no deeper reason than the rhyme in true blue (c. 1500). The figurative meaning "sad, sorrowful, afflicted with low spirits" is from c. 1400, perhaps from the "livid" sense and implying a bruised heart or feelings. Of women, "learned, pedantic," by 1788 (see bluestocking). In some phrases, such as blue murder, it appears to be merely intensive.

Few words enter more largely into the composition of slang, and colloquialisms bordering on slang, than does the word BLUE. Expressive alike of the utmost contempt, as of all that men hold dearest and love best, its manifold combinations, in ever varying shades of meaning, greet the philologist at every turn. [John S. Farmer, "Slang and Its Analogues Past and Present," 1890, p.252] 

Blue pencil as an editor's characteristic tool to mark corrections in copy is from 1885; also as a verb from 1885. The fabulous story of Blue-beard, who kept his murdered wives in a locked room, is in English from 1798. For blue ribbon see cordon bleu under cordon. Blue whale is attested from 1851, so called for its color. Blue cheese is from 1862. Blue water "the open ocean" is from 1822. Blue streak, of something resembling a bolt of lightning (for quickness, intensity, etc.) is from 1830, Kentucky slang. Delaware has been the Blue Hen State at least since 1830, supposedly from a nickname of its regiments in the Revolutionary War.

Old English cipp "small piece (of wood, stone etc.) separated from a body by a blow from an instrument," perhaps from PIE root *keipo- "sharp post" (source also of Dutch kip "small strip of wood," Old High German kipfa "wagon pole," Old Norse keppr "stick," Latin cippus "post, stake, beam;" the Germanic words perhaps were borrowed from Latin).

Meaning "small disk or counter used in a game of chance" is first recorded 1840. Meaning "piece of dried dung" first attested 1846, American English. Electronics sense "thin, tiny square of semi-conducting material" is from 1962.

Used for thin slices of foodstuffs (originally fruit) since 1769; specific reference to potatoes (what Americans would call French fries) is found by 1859 (in "A Tale of Two Cities"). The fish-and-chips combination was being offered in London by 1860. Potato-chip is attested by 1854, but the context doesn't make it clear whether this is the British version (above) or the U.S. version, "very thin slice of potato fried until crisp" (the British crisp). The American potato-chip is said to have been invented 1853 in Saratoga, N.Y., and is described, more or less, by this name in a recipe book from 1858. OED notes they also were called Saratoga chips (by 1880).

Chip of the old block, familiar term for a child or adult who resembles a parent in some way is used by Milton (1642); earlier form was chip of the same block (1620s); more common modern form of the phrase with off in place of of is by early 20c. To have a chip on one's shoulder is 1830, American English, from the custom of a boy determined to fight putting a wood chip on his shoulder and defying another to knock it off. When the chips are down (1940s) is from the chips being down on the table after the final bets are made in a poker match. Chips as a familiar name for a carpenter is from 1785.