Etymology
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scratch (v.)
c. 1400, probably a fusion of Middle English scratten and crachen, both meaning "to scratch," both of uncertain origin. Related: Scratched; scratching. Billiards sense of "to hit the cue ball into a pocket" is first recorded 1909 (also, originally, itch), though earlier it meant "a lucky shot" (1850). Meaning "to withdraw (a horse) from a race" is 1865, from notion of scratching name off list of competitors; used in a non-sporting sense of "cancel a plan, etc." from 1680s. To scratch the surface "make only slight progress in penetrating or understanding" is from 1882. To scratch (one's) head as a gesture of perplexity is recorded from 1712.
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Scratch (n.2)
in Old Scratch "the Devil," 1740, from earlier Scrat, from Old Norse skratte "goblin, wizard," a word which was used in late Old English to gloss "hermaphrodite;" probably originally "monster" (compare Old High German scraz, scrato "satyr, wood demon," German Schratt, Old High German screz "a goblin, imp, dwarf;" borrowed from Germanic into Slavic, as in Polish skrzat "a goblin").
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scratch (n.1)

1580s, "slight skin tear produced by a sharp thing," from scratch (v.). Meaning "mark or slight furrow in metal, etc." is from 1660s. American English slang sense of "money" is from 1914, of uncertain signification. Many figurative senses (such as up to scratch, originally "ready to meet one's opponent") are from sporting use for "line or mark drawn as a starting place," attested from 1778 (but the earliest use is figurative); meaning "nothing" (as in from scratch) is 1918, generalized from specific 19c. sporting sense of "starting point of a competitor who receives no odds in a handicap match." Sense in billiards is from 1850. Scratch-pad is attested from 1883.

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backscratcher (n.)
also back-scratcher, 1834; see back (n.) + scratch (v.).
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scratchy (adj.)
1710, "affected with 'the scratch,'" a skin disease, from scratch (n.1) + -y (2). Meaning "composed of scratches" is from 1827; that of "grating" is from 1866. Of sounds (especially in reproduction) from 1889. Related: Scratchiness.
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rive (v.)

"tear in pieces, strike asunder," c. 1200, from a Scandinavian or North Sea Germanic source akin to Old Norse rifa "to tear apart," from Proto-Germanic *rifanan "to tear, scratch" (compare Swedish rifva, Danish rive "scratch, tear"), from PIE root *rei- "to scratch, tear, cut" (see riparian).

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grate (v.)
"to scrape, rub," late 14c. (implied in grated), from Old French grater "to scrape, scratch (out or off); erase; destroy, pull down" (Modern French gratter), from Frankish *kratton, from Proto-Germanic *krattojan (source also of Old High German krazzon "to scratch, scrape," German kratzen "to scratch," Swedish kratta, Danish kratte "to rake, scrape"), probably of imitative origin. Senses of "sound harshly," and "annoy" are mid-16c. Italian grattare also is from Germanic. Related: Grated; grating.
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Cnidaria (n.)

phylum of stinging invertebrates, 1860, with abstract noun ending -ia + Latinized form of Greek knidē "nettle," from stem of knizein "to scratch scrape," which is of uncertain origin. Beekes compares Lithuanian knìsti "to scratch, itch, tickle," knisù "to grub up;" Latvian knidet "to itch, geminate, creep;" Old Norse hnita "to push against;" Middle Irish cned "wound." Related: Cnidarian.

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write (v.)

Old English writan "to score, outline, draw the figure of," later "to set down in writing" (class I strong verb; past tense wrat, past participle writen), from Proto-Germanic *writan "tear, scratch" (source also of Old Frisian writa "to write," Old Saxon writan "to tear, scratch, write," Old Norse rita "write, scratch, outline," Old High German rizan "to write, scratch, tear," German reißen "to tear, pull, tug, sketch, draw, design"), outside connections doubtful.

For men use to write an evill turne in marble stone, but a good turne in the dust. [More, 1513]

Words for "write" in most Indo-European languages originally mean "carve, scratch, cut" (such as Latin scribere, Greek graphein, glyphein, Sanskrit rikh-); a few originally meant "paint" (Gothic meljan, Old Church Slavonic pisati, and most of the modern Slavic cognates). To write (something) off (1680s) originally was from accounting; figurative sense is recorded from 1889. Write-in "unlisted candidate" is recorded from 1932.

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gratin (n.)
light crust over a dish, 1806 (in au gratin), from French gratin "crust" (16c.), from gratter "to scrape, scratch" (see grate (v.)).
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