Old English strican (past tense strac, past participle stricen) "pass lightly over, stroke, smooth, rub," also "go, move, proceed," from Proto-Germanic *strikan- (source also of Old Norse strykva "to stroke," Old Frisian strika, Middle Dutch streken, Dutch strijken "to smooth, stroke, rub," Old High German strihhan, German streichen), from PIE root *strig- "to stroke, rub, press" (see strigil). Related to streak and stroke, and perhaps influenced in sense development by cognate Old Norse striuka.
Sense of "to deal a blow" developed by early 14c.; meaning "to collide" is from mid-14c.; that of "to hit with a missile" is from late 14c. Meaning "to cancel or expunge" (as with the stroke of a pen) is attested from late 14c. A Middle English sense is preserved in strike for "go toward." Sense of "come upon, find" is from 1835 (especially in mining, well-digging, etc., hence strike it rich, 1854). Baseball sense is from 1853. To strike a balance is from the sense "balance accounts" (1530s).
Meaning "refuse to work to force an employer to meet demands" is from 1768, perhaps from notion of striking or "downing" one's tools, or from sailors' practice of striking (lowering) a ship's sails as a symbol of refusal to go to sea (1768), which preserves the verb's original sense of "make level, smooth."
1560s, "directed downward," from down (adv.). Sense of "depressed mentally" is attested from c. 1600. Slang sense of "aware, wide awake" is attested from 1812. Computer crash sense is from 1965. Down-and-out "completely without resources" is from 1889, American English, from situation of a beaten prizefighter.
1710, "a downward movement," from down (adv.). Football sense of "an attempt to advance the ball" is by 1882.
"in a descending direction, from a higher to a lower place, degree, or condition," late Old English shortened form of Old English ofdune "downwards," originally of dune "off from (the) hill," from dune "from the hill," dative of dun "hill" (see down (n.2)). The "hill" word is general in Germanic, but this sense development is peculiar to English. As a preposition, "in a descending direction upon or along," from late 14c.
To be down on "express disapproval of" is by 1851. Down home is from 1828 as "in one's home region," as an adjective phrase meaning "unpretentious" by 1931, American English. Down the hatch as a toast is from 1931. Down to the wire is 1901, from horse-racing.
Down Under "Australia and New Zealand" attested from 1886; Down East "Maine" is from 1825; Down South "in the Southern states of the U.S." is attested by 1834. Down the road "in the future" is by 1964, U.S. colloquial. Down-to-earth "everyday, ordinary, realistic" is by 1932.
1560s, "cause to go down," from down (adv.). Meaning "swallow hastily" is by 1860; football sense of "bring down (an opposing player) by tackling" is attested by 1887. Figurative sense of "defeat, get the better of" is by 1898. Related: Downed; downing.
"first feathers of a baby bird; soft covering of fowls under the feathers, the under-plumage of birds," used for stuffing pillows and feather-beds, mid-14c., from Old Norse dunn, which is of uncertain origin. Extended in Modern English to the soft hair of the human face and fine soft pubescence upon plants and some fruit.
"a hill of moderate elevation and more or less rounded outline," Old English dun "height, hill, moor," from Proto-Germanic *dunaz- (source also of Middle Dutch dunen "sandy hill," Dutch duin), "probably a pre-insular loan-word from Celtic" [Cambridge Dictionary of English Place-Names], in other words, borrowed at a very early period, before the Anglo-Saxon migration, perhaps from PIE root *dheue- "to close, finish, come full circle."
The more general meaning "elevated rolling grassland; high, rolling region not covered by forest" is from c. 1400. Specifically of certain natural pastureland districts of south and southeast England (the Downs) by mid-15c.
The non-English Germanic words tend to mean "dune, sand bank" (see dune), while the Celtic cognates tend to mean "hill, citadel" (compare Old Irish dun "hill, hill fort;" Welsh din "fortress, hill fort;" and second element in place names London, Verdun, etc.). German Düne, French dune, Italian, Spanish duna are said to be loan-words from Dutch.