Online Etymology Dictionary

strobe (n.): 1942, shortening of stroboscope. As a shortened form of strobe light, from 1949. As an adjective from 1942.
strobic (adj.): "resembling a top," 1876, from Greek strobos (see stroboscope) + -ic.
stroboscope (n.): "instrument for studying motion by periodic light," 1896, from -scope + comb. form of Greek strobos "a twisting, act of whirling," from PIE *streb(h)- "to wind, turn" (see strophe). Earlier as the name of a similar device used as a "scientific toy" [OED]. Related: Stroboscopic (1846).
strode: past tense of stride (v.).
stroganoff (n.): a beef dish cooked in sauce containing sour cream, 1932, from French, from name of the prominent Russian family, usually said to be for specifically in honor of diplomat Count Paul Stroganov (1774-1817).
stroke (n.): "act of striking," c. 1300, probably from Old English *strac "stroke," from Proto-Germanic *straik- (source also of Middle Low German strek, German streich, Gothic striks "stroke"); see stroke (v.).

The meaning "mark of a pen" is from 1560s; that of "a striking of a clock" is from mid-15c. Sense of "feat, achievement" (as in stroke of luck, 1853) first found 1670s; the meaning "single pull of an oar or single movement of machinery" is from 1731. Meaning "apoplectic seizure" is from 1590s (originally the Stroke of God's Hand). Swimming sense is from 1800.
stroke (v.): "pass the hand gently over," Old English stracian "to stroke," related to strican "pass over lightly," from Proto-Germanic *straik-, from PIE root *streig- "to stroke, rub, press" (see strigil). Figurative sense of "soothe, flatter" is recorded from 1510s. The noun meaning "a stroking movement of the hand" is recorded from 1630s. Related: Stroked; stroking.
stroll (v.): c. 1600, a cant word introduced from the Continent, probably from dialectal German strollen, variant of Swiss German strolchen "to stroll about, loaf," from Strolch "vagabond, vagrant," also "fortuneteller," perhaps from Italian astrologo "astrologer." Related: Strolled; strolling.
stroll (n.): 1753, from stroll (v.).
stroller (n.): c. 1600, "strolling player;" 1670s, "one who strolls, a wanderer," agent noun from stroll (v.). Meaning "child's push-chair" is from 1920.
stroma (n.): 1835 in anatomy, plural stromae, Modern Latin, from Latin stroma "bed covering," from Greek stroma "coverlet, covering, mattress, anything spread out for lying or sitting on" (see structure (n.)).
strong (adv.): Old English strange "strongly, violently, severely, furiously" (alongside strongly), from the same source as strong (adj.). Going strong (1898) is from racing. To come on strong was originally come it strong (1812).
strong (adj.): Old English strang "physically powerful, powerful in effect; forceful, severe, firm, bold, brave; constant, resolute; arduous, violent," from Proto-Germanic *strangaz (source also of Old Norse strangr "strong," Dutch streng "strict, rigorous," Old High German strang "strong, bold, hard," German streng "strict, rigorous"), possibly from PIE *strenk- "tight, narrow." Originally compared strenger, strengest (compare old/elder/eldest).

Grammatical sense, of noun and verb inflections, is first attested 1841, translating German stark, used in a grammatical sense by J. Grimm (the terms strong and weak better fit German inflections). Strong suit (1865) is from card-playing. Strong man "man of great strength" (especially one who displays it professionally) is recorded from 1690s; meaning "dominating man in a political organization" is from 1859.
strong-arm (adj.): "using physical force," 1897, from noun phrase (c. 1600), from strong (adj.) + arm (n.). As a verb from 1903. Related: Strong-armed; strong-arming.
strong-box (n.): 1680s, from strong (adj.) + box (n.1).
stronghold (n.): early 14c., from strong (adj.) + hold (n.) "fortified place, refuge."
strongly (adv.): Old English stranglice "firmly, stoutly, boldly, bravely;" see strong (adj.) + -ly (2).
strontium (n.): light metallic element, 1808, coined in Modern Latin by English chemist Sir Humphry Davy (1778-1829) from Strontian, name of a parish in Argyllshire, Scotland, the site of lead mines where strontium was first found, in 1787.
strop (n.): mid-14c., "loop or strap on a harness," probably from Old French estrop, making it the older and more correct form of strap (n.), replaced by it from 16c. Specific sense of "leather strap used for sharpening razors" first recorded 1702. The verb in this sense is from 1841. Related: Stropped; stropping. Distribution of senses between strap and strop is arbitrary.
strophe (n.): c. 1600, from Greek strophe "stanza," originally "a turning," in reference to the section of an ode sung by the chorus while turning in one direction, from strephein "to turn," from PIE *streb(h)- "to wind, turn" (source also of Greek strophaligs "whirl, whirlwind," streblos "twisted," stremma "that which is twisted").
strophic (adj.): 1810, from strophe + -ic.
stroppy (adj.): "rebellious," by 1943, British nautical slang, perhaps a slang mangling of obstreperous. "Sea Passages: A Naval Anthology and Introduction to the Study of English" [1943, Geoffrey Callender] quotes from a letter:
Why Nobby should reckon that his raggie should blow the gaff, when there are crushers everywhere, leaves me guessing; but there it is. In the last dog he rounded on me and called me a white rat. I got stroppy and told him he was shooting a line: but all he said was, 'Oh! choke your luff! I'm looking for another oppo you snivelling sand-catcher.' So that looks like paying off.
to which Callender adds, "There is nothing in this letter which an active service rating could fail to understand."
strove: past tense of strive (v.).
struck: past tense and past participle of strike (v.).
structural (adj.): 1814, from structure + -al (1). Related: Structurally.
structuralism (n.): 1891, from structural + -ism.
structure (n.): mid-15c., "action or process of building or construction;" 1610s, "that which is constructed, a building or edifice;" from Latin structura "a fitting together, adjustment; a building, mode of building;" figuratively, "arrangement, order," from structus, past participle of struere "to pile, place together, heap up; build, assemble, arrange, make by joining together," related to strues "heap," from PIE *stere- "to spread, extend, stretch out."

The widespread descendants of this ancient root are believed to include: Sanskrit strnoti "strews, throws down;" Avestan star- "to spread out, stretch out;" Greek stronymi "strew," stroma "bedding, mattress," sternon "breast, breastbone;" Latin sternere "to stretch, extend;" Old Church Slavonic stira, streti "spread," strama "district;" Russian stroji "order;" Gothic straujan, Old High German strouwen, Old English streowian "to sprinkle, strew;" Old English streon "strain," streaw "straw, that which is scattered;" Old High German stirna "forehead," strala "arrow, lightning bolt;" Old Irish fo-sernaim "spread out," srath "a wide river valley;" Welsh srat "plain."
structure (v.): "put together systematically," by 1855 (occasional use from late 16c.), from structure (n.). Related: Structured; structuring.
structured (adj.): 1810, past participle adjective from structure (v.). Meaning "organized so as to produce results" is from 1959.
strudel (n.): kind of Austrian pastry, 1893, from German Strudel, literally "eddy, whirlpool," from Old High German stredan "to bubble, boil, whirl, eddy," from PIE root *ser- (2) "to flow" (see serum).
struggle (v.): late 14c., of uncertain origin, probably a frequentative form with -el (3) (compare trample, wrestle), but the first element is of uncertain origin. Skeat suggests Old Norse strugr "ill will;" others suggest a connection to Dutch struikelen, German straucheln "to stumble." Related: Struggled; struggling.
struggle (n.): 1690s, from struggle (v.).
Struldbrug (n.): "person who never dies but becomes senile and useless," 1726, from "Gulliver's Travels," a made-up word.
strum (v.): 1775, possibly imitative of the sound of running the fingers across the strings of a musical instrument. Related: Strummed; strumming. As a noun from 1793.
strumpet (n.): "harlot; bold, lascivious woman," early 14c., of uncertain origin. One theory connects it with Latin stuprata, fem. past participle of stuprare "have illicit sexual relations with," or Late Latin strupum "dishonor, violation." But evidence for this is wanting and others suggest Middle Dutch strompe "a stocking," or strompen "to stride, to stalk" (as a prostitute might a customer). The major sources don't seem to give much preference to any of these. Weekley notes "Gregory's Chronicle (c. 1450) has streppett in same sense." In 18c.-early 19c., often abbreviated as strum and also used as a verb, which led to some odd dictionary entries:
TO STRUM: to have carnal knowledge of a woman, also to play badly on the harpsichord or any other stringed instrument. [Capt. Francis Grose, "A Classical Dictionary of the Vulgar Tongue," 1785]
strung: past tense and past participle of string (v.). From 1680s as an adjective; in reference to nerves, feelings, etc., from 1840. Strung out is from 1902 as "spread out in a line;" slang meaning "addicted" is recorded from 1959.
strut (v.): "walk in a vain, important manner, walk with affected dignity," 1590s, from Middle English strouten "display one's clothes proudly, vainly flaunt fine attire" (late 14c.), earlier "to stick out, protrude, bulge, swell," from Old English strutian "to stand out stiffly, swell or bulge out," from Proto-Germanic *strut- (source also of Danish strutte, German strotzen "to be puffed up, be swelled," German Strauß "fight"), from PIE root *ster- (1) "strong, firm, stiff, rigid" (see stereo-).

Originally of the air or the attitude; modern sense, focused on the walk, first recorded 1510s. Related: Strutted; strutting. To strut (one's) stuff is first recorded 1926, from strut as the name of a dance popular from c. 1900. The noun meaning "a vain and affectedly dignified manner of walking" is from c. 1600.
strut (n.): "supporting brace," 1580s, perhaps from strut (v.), or a cognate word in Scandinavian (compare Norwegian strut "a spout, nozzle") or Low German (compare Low German strutt "rigid"); ultimately from Proto-Germanic *strutoz-, from root *strut- (see strut (v.)).
struthious (adj.): "of the ostrich," 1773, from Latin struthio "ostrich," from Greek strouthion (see ostrich) + -ous.
Struwwelpeter (n.): German, name of a character in the children's book by Heinrich Hoffman (1809-1894). There was an English edition by 1848.
strychnine (n.): powerful poisonous alkaloid, 1819, from French strychnine, from Modern Latin Strychnos, the genus name of the plant (nux vomica) from which the poison is obtained, from Greek strychnon, a kind of nightshade, of uncertain origin. The chemical was discovered 1818 by Pelletier and Caventou in the Asian tree Strychnos ignatii.
Stuart: name of the British royal family from 1603 to 1668; see steward. Attested from 1873 as an attribution for styles from that period.
stub (n.): Old English stybb "stump of a tree," from Proto-Germanic *stubjaz (source also of Middle Dutch stubbe, Old Norse stubbr), from PIE root *(s)teu- (1) "to push, stick, knock, beat" (see steep (adj.)). Extended 14c. to other short, thick, protruding things. Meaning "remaining part of something partially consumed" is from 1520s.
stub (v.): mid-15c., "dig up stumps, dig up by the roots," from stub (n.). The sens of "strike (one's toe) against" something projecting from a surface is first recorded 1848. Meaning "to extinguish a cigarette" is from 1927. Related: Stubbed; stubbing.
stubble (n.): c. 1300, "stumps of grain stalks left in the ground after reaping," from Old French estuble "stubble" (Modern French éteule), from Vulgar Latin stupla, reduced form of Latin stipula "stalk, straw" (see stipule). Applied from 1590s to bristles on a man's unshaven face.
stubbly (adj.): c. 1600, from stubble (n.) + -y (2). Related: Stubbliness.
stubborn (adj.): late 14c., of uncertain origin. Earliest form is stiborn. OED, Liberman doubt any connection with stub (n.). Related: Stubbornly; stubbornness.
stubby (adj.): "short and thick," 1570s, from stub (n.) + -y (2); of persons, from 1831.
stucco (n.): fine plaster used as a wall coating, 1590s, from Italian stucco, from a Germanic source (compare Old High German stukki "crust, piece, fragment"), from Proto-Germanic *stukkjam, from PIE root *(s)teu- (1) "to push, stick, knock, beat" (see stock (n.1)). The verb is attested from 1726. Related: Stuccoed; stuccoing.
stuck (adj.): "unable to go any further," 1885, past participle adjective from stick (v.). Colloquial stuck-up "offensively conceited, assuming an unjustified air of superiority" is recorded from 1829.