Etymology
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coincidence (n.)

c. 1600, "exact correspondence in substance or nature," from French coincidence, from coincider, from Medieval Latin coincidere, literally "to fall upon together," from assimilated form of  Latin com "with, together" (see com-) + incidere "to fall upon" (from in- "upon" + combining form of cadere "to fall," from PIE root *kad- "to fall").

From 1640s as "occurrence or existence during the same time." Meaning "a concurrence of events with no apparent connection, accidental or incidental agreement" is from 1680s, perhaps first in writings of Sir Thomas Browne.

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coincidental (adj.)

"pertaining to or of the nature of coincidence," c. 1800, from coincident + -al (1).

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squint (n.)
"non-coincidence of the optic axes," 1650s, from squint (adj.). Meaning "sidelong glance" is from 1660s.
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consilience (n.)

1840, "concurrence, coincidence," literally "a jumping together," formed on model of resilience from Latin consilient-, from assimilated form of com "with, together" (see con-) + salire "to leap" (see salient (adj.)).

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emoji (n.)

pictorial character, by 2008, from Japanese e "picture" + moji "character" (compare kanji), coined 1999 in Japanese by Shigetaka Kurita, NTT DoCoMo employee. Its adoption in English was driven by Apple iPhone's inclusion of the feature in 2008. The similarity to native emoticon is a happy coincidence.

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myopia (n.)

"short-sightedness," 1727, medical Latin, from Late Greek myōpia "near-sightedness," from myōps "near-sighted," literally "closing the eyes, blinking," on the notion of "squinting, contracting the eyes" (as near-sighted people do), from myein "to shut" (see mute (adj.)) + ōps (genitive ōpos) "eye" (from PIE root *okw- "to see"). By coincidence the name describes the problem: the parallel rays of light are brought to a focus before they reach the retina.

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coolie (n.)

name given by Europeans to hired native laborers employed in menial work in India and China, c. 1600, according to OED from Hindi quli "hired servant," probably from kuli, name of an aboriginal tribe or caste in Gujarat. The name was picked up by the Portuguese, who used it in southern India (where by coincidence kuli in Tamil meant "hire") and in China.

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chad (n.2)

"hanging flap or piece after a hole is punched in paper," a word unknown to most people until the 2000 U.S. presidential election (when the outcome hinged on partially punched paper ballots in some Florida counties), attested by 1930, of unknown origin. Perhaps it is not a coincidence that the word is identical to an English dialectal variant of chat, meaning "a dry twig; dry fragments among food."

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loafer (n.)
"idler, person who loafs," 1830, of uncertain origin, often regarded as a shortened variant of land loper (1795), a partial loan-translation of German Landläufer "vagabond," from Land "land" + Läufer "runner," from laufen "to run" (see leap (v.)). But OED finds this connection "not very probable." As a type of shoe for informal occasions, 1937. Related: Loafers. By coincidence Old English had hlaf-aeta "household servant," literally "loaf-eater;" one who eats the bread of his master, suggesting the Anglo-Saxons might have still felt the etymological sense of lord as "loaf-guard."
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concurrence (n.)

early 15c., "a combination for some purpose, cooperation" (a sense now archaic or obsolete), from Old French concurrence (14c.) or directly from Medieval Latin concurrentia "a running together," from concurrens, present participle of concurrere "to run together, assemble hurriedly; clash, fight," in transferred use, "to happen at the same time," from assimilated form of com "together" (see con-) + currere "to run" (from PIE root *kers- "to run").

Sense of "occurrence together in time, coincidence" is from c. 1600. Meaning "accordance in opinion" is from 1660s.

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