Online Etymology Dictionary

strength: O.E. strengþu "power, force, vigor, moral resistance," from P.Gmc. *strangitho (cf. O.H.G. strengida "strength"), in gradational relationship to the root of strong. Verb strengthen is recorded from c.1300.
courage: c.1300, from O.Fr. corage, from V.L. *coraticum, from L. cor "heart," which remains a common metaphor for inner strength. In M.E., used broadly for "what is in one's mind or thoughts," hence "bravery," but also "wrath, pride, confidence, lustiness," or any sort of inclination. Replaced O.E. ellen, which also meant "zeal, strength."
-cracy: from M.L. -cratia, from Gk. -kratia "power, rule," from kratos "strength," from PIE *kratus "power, strength" (see hard). The connective -o- has come to be viewed as part of it.
tour (n.): c.1320, "a turn, a shift on duty," from O.Fr. tour, tourn "a turn, trick, round, circuit, circumference," from torner, tourner "to turn," from L. tornare "to polish, round off, fashion, turn on a lathe" (see turn). Sense of "a traveling around, journey" is first recorded 1643. The verb is attested from 1746. Tour de force "feat of strength" is 1802, from Fr., from force "strength." Tour de France is recorded from 1922. The Grand Tour, a journey through France, Germany, Switzerland, and Italy formerly was the finishing touch in the education of a gentleman.
jism: "cum," 1899; earlier "energy, strength" (1842), see jazz.
exhaustion: "fatigue," 1640s, from exhaust in sense of "drawing off" of strength.
mensch: "person of strength and honor," 1909, from Yiddish, from Ger., lit. "man, person."
corrugated: 1620s, "wrinkled" (of skin, etc.), pp. adj. from corrugate. Meaning "bent into curves or folds" (of iron, cardboard, etc., for elasticity and strength) is from 1853.
ammeter: instrument for measuring the strength of electric currents, 1882, from am(pere) + meter.
beef up (v.): "add strength," 1941, from college slang, from beef (n.) in slang sense of "muscle-power" (1851).
belabor: c.1600, "to exert one's strength upon," from be- + labor. But figurative sense of "assail with words" is attested somewhat earlier (1590s).
backbone: "spine," c.1300, from back (n.) + bone. Fig. sense of "strength of character" is attested from 1843.
vim: 1843, usually said to be from L. vim, accusative of vis "strength, force, power, energy." But perhaps the modern word is purely imitative.
unnerve: 1621, "to destroy the strength of," from un- (2) + nerve. Meaning "to deprive of courage" is recorded from 1704.
Alcestis: wife of Admetus, she offered her life for her husband and was rescued from the Underworld by Herakles, from Gk. Alkestis, lit. "valiant, courageous," from alke "protection, help, strength, power."
amperage: strength of an electric current, 1894, from ampere on model of voltage.
overreach: c.1300, "to reach above or beyond" (trans.), from over + reach (q.v.). Meaning "to extend over something, to cover it" is from c.1400. Sense of "to reach beyond one's strength" is from 1568.
re-enforce: c.1586, "to give fresh strength to," from re- "back, again" + enforce (q.v.). Originally of persons or military units; of buildings, structures, etc., attested from 1883.
pall (v.): "become tiresome," 1700, from M.E. pallen "to become faint, fail in strength" (1390), aphetic form of appallen "to dismay, fill with horror or disgust" (see appall).
ripsnorter: "something of exceptional strength," 1840, probably from rip (v.) + snort (q.v.).
hard (adj.): O.E. heard "solid, firm, not soft," also "severe, rigorous, cruel," from P.Gmc. *kharthus (cf. Du. hard, O.N. harðr "hard," O.H.G. harto "extremely, very," Goth. hardus "hard"), from PIE *kratus "power, strength" (cf. Gk. kratos "strength," kratys "strong"). The adv. sense was also present in O.E. Hard of hearing preserves obsolete M.E. sense of "having difficulty in doing something." Hard liquor is 1879, Amer.Eng. (hard cider is from 1789), and this probably led to hard drugs (1955). Hard facts is from 1887; hard news is from 1938. Hard-headed is first attested 1519; hard-hearted is c.1200. Hard-boiled "severe, tough" is from 1886; hard-core "tough" is 1951, extension to pornography is from 1970s. Hard up (1610s) is originally nautical, of steering (slang sense of "short of money" is from 1821), as is hard and fast (1867), of a ship on shore. Hardball in the figurative sense of "tough, uncompromising" is from 1973; hard-on "penile erection" first recorded 1893; hard times "period of poverty" is from 1705. Hard hat was originally (1935) "derby;" meaning "safety helmet" is from 1953; used figuratively for "construction worker" from 1970. Hard-wired is 1969, from computing. Hardscrabble "barren place" is first recorded 1804, in journals of Lewis and Clark.
Bridget: fem. proper name, from Ir. Brighid, fire goddess, from brigh "strength," from Celt. *brig-o-.
titration: 1864, from Fr. titrer, from titre "standard, title" (see title), also "fineness of alloyed gold;" in chemistry, the establishment of a standard strength or degree of concentration of a solution.
Samson: masc. proper name, Biblical strong-man (Judges xiii-xvi), from L.L., from Gk. Sampson, from Heb. Shimshon, probably from shemesh "sun." As a generic name for a man of great strength, attested from 1565. Samsonite, proprietary name for a make of luggage, is 1939, by Shwayder Bros. Inc., Denver, U.S.
unwieldy: late 14c., "lacking strength," from un- (1) "not" + O.E. wielde "active, vigorous," from P.Gmc. *walth- "have power" (see wield). Meaning "moving ungracefully" is recorded from 1530; in ref. to weapons, "difficult to handle, awkward by virtue of size or shape" it is attested from 1547.
ochlocracy: "government by the rabble," 1584, from Fr. ochlocratie (1568), from Gk. okhlokratia, from okhlos "mob" + kratos "rule, power, strength" (see -cracy).
brio: "liveliness, vivacity," 1734, from It., lit. "mettle, fire, life," perhaps an aphetic derivative of L. ebrius "drunk." Or via Prov. briu "vigor," from Celt. *brig-o- "strength." Probably entered Eng. via musical instruction con brio.
Humphrey: masc. proper name, from O.E. Hunfrið, probably from P.Gmc. *hun "strength" + O.E. frið "peace." To dine with Duke Humphrey (17c.) meant to go without a meal, though the reason for the expression now is obscure.
valence: c.1425, "extract, preparation," from L. valentia "strength, capacity," from valentem (nom. valens), prp. of valere "be strong" (see valiant). Meaning "combining power of an element" is recorded from 1884, from Ger. Valenz (1868), from the L. word.
robust: 1549, from L. robustus "strong and hardy," originally "oaken," from robur, robus "hard timber, strength," also "a special kind of oak," named for its reddish heartwood, from L. ruber "red" (cf. robigo "rust"). Robustious (1548) was a common form in 17c. (cf. "Hamlet" iii.2); it fell from use by mid-18c., but was somewhat revived by mid-19c. antiquarian writers.
craft: O.E. cræft "power, strength, might," from P.Gmc. *krab-/*kraf-. Sense shifted to "skill, art" (via a notion of "mental power"), which led to the n. meaning of "trade." Use for "small boat" is first recorded 1671, probably from some nautical sense of "vessels of small craft," referring either to the trade they did or the seamanship they required.
Arnold: masc. proper name, from Ger., from O.H.G. Arenwald, lit. "having the strength of an eagle," from O.H.G. aro "eagle" + wald "power" (see wield).
calisthenics: 1839, formed on model of Fr. callisthenie, from Gk. kallos "beauty" + sthenos "strength." Originally, gymnastic exercises suitable for girls and meant to develop the figure; training calculated to develop the figure and promote graceful movement. The proper Gk., if there was such a word in Gk., would have been kallistheneia.
Mildred: fem. proper name, O.E. Mildðryð, from milde "mild" + ðryð "power, strength." A popular name in the Middle Ages through fame of St. Mildred (obit c. 700), abbess, daughter of a Mercian king and a Kentish princess. Among the 10 most popular names for girls born in the U.S. between 1903 and 1926, it hasn't been in the top 1,000 since 1983.
Audrey: fem. proper name, contracted from Etheldreda, a Latinized form of O.E. Æðelðryð, lit. "noble might," from æðele "noble" + ðryð "strength, might."
violation: 1432, from L. violationem (nom. violatio) "an injury, irreverence," from violatus, pp. of violare "to violate, treat with violence, outrage, dishonor," perhaps related to vis "violence, strength."
fortitude: 1422, from M.Fr. fortitude, from L. fortitudo "strength," from fortis "strong, brave" (see fort).
Hebe: 1606, Gk. goddess of youth, from Gk. hebe "youth, strength of youth;" hence hebephrenia "adolescent insanity" (1886), coined in Mod.L. by Ger. psychiatrist Ewald Escker in 1871, from Gk. phrene (gen. phrenos) "mind."
theocracy: 1622, "sacerdotal government under divine inspiration" (as that of Israel before the rise of kings), from Gk. theokratia "the rule of God" (Josephus), from theos "god" (see Thea) + kratos "a rule, regime, strength" (see -cracy). Meaning "priestly or religious body wielding political and civil power" is recorded from 1825.
berserk: 1822, introduced by Sir Walter Scott, from O.N. berserkr (n.) "raging warrior of superhuman strength," probably from *ber- "bear" + serkr "shirt," thus lit. "a warrior clothed in bearskin." The -r was O.N. masc. singular ending, mistaken for agent noun suffix. The adj. is 1867, from such phrases as go berserk.
neuro-: Gk. neuro-, comb. form of neuron "nerve," originally "sinew, tendon, cord, bowstring," also "strength, vigor," from PIE *sneurom (cf. L. nervus; see nerve).
asthenia: "weakness," 1789 (in asthenic), Mod.L., from Gk. asthenia, from asthenes "weak," from a-, privative prefix, + sthenos "strength," of uncertain origin.
democracy: 1570s, from M.Fr. democratie, from M.L. democratia (13c.), from Gk. demokratia, from demos "common people," originally "district" (see demotic), + kratos "rule, strength" (see -cracy).
kakistocracy: 1829, "government by the worst element of a society," coined on analogy of aristocracy from Gk. kakistos "worst," superl. of kakos "bad" (which is perhaps related to the general IE word for "defecate") + -kratia "rule of," from kratos "strength, power, rule" (see -cracy).
steer (n.): "young ox," O.E. steor "bullock," from P.Gmc. *steuraz (cf. O.S. stior, O.N. stjorr, Swed. tjur, Dan. tyr, M.Du., Du., Ger. stier, Goth. stiur "bull"), perhaps from PIE *steu-ro-, a base denoting "strength, sturdiness" (see taurus).
ambivalence: "simultaneous conflicting feelings," 1924, from Ger. Ambivalenz, coined 1910 by Swiss psychologist Eugen Bleuler (1857–1939) on model of Ger. Equivalenz "equivalence," etc., from L. ambi- "both" (see ambi-) + valentia "strength," from prp. of valere "be strong" (see valiant). A psychological term that by 1929 had taken on a broader literary and general sense.
autocrat: 1803, from Fr. autocrate, from Gk. autokrates "ruling by oneself," from autos- "self" (comb. form) + kratia "rule," from kratos "strength, power" (see -cracy). First used by Robert Southey, with reference to Napoleon. An earlier form was autocrator (1789), used in ref. to the Russian Czars. Earliest form in Eng. is the fem. autocratress (1762).
attrition: 1540s, "abrasion, a scraping," from L. attritionem (nom. attritio), lit. "a rubbing against," noun of action from attritus pp. of atterere "to wear, rub away," from ad- "to" + terere "to rub" (see throw). The earliest sense in Eng. is from Scholastic theology (late 14c.), "sorrow for sin merely out of fear of punishment," a minor irritation, and thus less than contrition. The sense of "wearing down an enemy's strength" is a World War I coinage (1914).
main (n.): O.E. mægen (n.) "power, strength, force," from P.Gmc. *maginam- "power," from *mag- "be able, have power" (see may). Original sense preserved in phrase with might and main. Meaning "principal channel in a utility system" is first recorded 1727 in main drain; Used since 1548 for "continuous stretch of land or water."
debility: late 15c., from M.Fr. debilite, from L. debilitatem (nom. debilitas), from debilis "weak," from de- "from, away" + -bilis "strength," from PIE base *bel- (see Bolshevik).