Online Etymology Dictionary

strength (n.): Old English strengþu, strengð "bodily power, force, vigor, firmness, fortitude, manhood, violence, moral resistance," from Proto-Germanic *strangitho (source also of Old High German strengida "strength"), from PIE *strenk- "tight, narrow" (see string (n.)), with Proto-Germanic abstract noun suffix *-itho (see -th (2)). Compare length/long. From the same root as strong,
strengthen (v.): late 14c., from strength + -en (1). Related: Strengthened; strengthening; strengthener. Earlier verb was simply strength (12c.).
wrath (n.): Old English wræððu "anger," from wrað "angry" (see wroth) + -þu, from Proto-Germanic -itho (as in strength, width etc.; see -th (2)).
-th (2): suffix forming nouns of action, state, or quality from verbs or adjectives (such as depth, strength, truth), from Old English -ðu, -ð, from Proto-Germanic *-itho (cognates: Old Norse -þ, Old High German -ida, Gothic -iþa), abstract noun suffix, from PIE *-ita (cognates: Sanskrit -tati-; Greek -tet-; Latin -tati-, as in libertatem "liberty" from liber "free"). Sometimes in English reduced to -t, especially after -h- (as in height).
berth (n.): 1620s, "convenient sea room" (both for ships and sailors), of uncertain origin, probably from bear (v.) + abstract noun suffix -th (2) as in strength, health, etc. Original sense is preserved in phrase to give (something or someone) wide berth. Meaning "place on a ship to stow chests, room for sailors" is from 1706; extended to non-nautical situations by 1778.
force majeure (n.): 1883, French, literally "superior strength."
ripsnorter (n.): "something of exceptional strength," 1840, probably from rip (v.) + snort (v.).
ammeter (n.): instrument for measuring the strength of electric currents, 1882, from ampere + -meter.
amperage (n.): strength of an electric current, 1889, from ampere on model of voltage.
tour de force (n.): "feat of strength," 1802, French; see tour (n.) + force (n.).
asthenia (n.): "weakness," 1802, Modern Latin, from Greek asthenia "want of strength, weakness, feebleness, sickness; a sickness, a disease," from asthenes "weak, without strength, feeble," from a-, privative prefix (see a- (3)), + sthenos "strength," which is probably from PIE *segh- "to hold" (see scheme (n.)).
backbone (n.): "spine," early 14c., from back (n.) + bone (n.). Figurative sense of "strength of character" is attested from 1843.
jism (n.): "seminal fluid, cum," 1899; earlier "energy, strength" (1842), of uncertain origin; see jazz (n.).
fortitude (n.): early 15c., from Middle French fortitude, from Latin fortitudo "strength, force, firmness, manliness," from fortis "strong, brave" (see fort).
titration (n.): in chemistry, "the establishment of a standard strength or degree of concentration of a solution," 1864, noun of action from titrate (v.).
muscle (v.): 1913, "to accomplish by strength," from muscle (n.). Related: Muscled; muscling. To muscle in is 1929 in underworld slang.
asthenic (adj.): 1789, from Modern Latin, from Greek asthenikos, from asthenes "weak, without strength, feeble" (see asthenia).
validity (n.): 1540s, from Middle French validité or directly from Late Latin validitatem (nominative validitas) "strength," from Latin validus (see valid).
fortitudinous (adj.): "capable of endurance," 1752, from Latin fortitudinem (nominative fortitudo) "strength, firmness" (see fortitude) + -ous. Related: Fortitudinously.
beef up (v.): "add strength," 1941, from college slang, from beef (n.) in slang sense of "muscle-power" (1851).
Gaza: Arabic form of Hebrew 'az "force, strength." Gaza Strip was created by the division of 1949.
Etheldred: Anglo-Saxon fem. proper name, Old English Æðelðryð, literally "of noble strength" (see Audrey).
puissance (n.): early 15c., "power, strength, authority," from Old French puissance, poissance "power, might" (12c.), from puissant (see puissant).
stout (n.): 1670s, "strong beer or ale," from stout (adj.). Later especially, and now usually, "porter of extra strength" (by 1762).
overwork (n.): "work beyond a person's strength," 1819; see overwork (v.). Old English oferweorc meant "a superstructure, sarcophagus, tomb."
Hebe (1): c. 1600, Greek goddess of youth, daughter of Zeus and Hera, wife of Hercules, from Greek hebe "youth, youthful prime, strength of youth" (legally, "the time before manhood," in Athens 16, in Sparta 18), from PIE *yeg-wa- "power, youth, strength."
Arnold: masc. proper name, from Old High German Arenwald, literally "having the strength of an eagle," from arn "eagle" (see erne) + wald "power" (see wield).
Audrey: fem. proper name, contracted from Etheldreda, a Latinized form of Old English Æðelðryð, literally "noble might," from æðele "noble" (see atheling) + ðryð "strength, might."
unnerve (v.): 1620s, "to destroy the strength of," from un- (2) "reverse, opposite of" + nerve (v.). Meaning "to deprive of courage" is recorded from 1704. Related: Unnerved; unnerving.
Herculean (adj.): 1590s, from Hercules + -an. "Of enormous size or strength or great courage," also sometimes "very difficult or dangerous," in allusion to the hero's labors.
dynamism (n.): 1831, "dynamic energy, force, drive," from Greek dynamis "power, might, strength" (see dynamic (adj.)) + -ism. As a philosophical system, from 1857.
nerve (v.): c. 1500, "to ornament with threads;" see nerve (n.). Meaning "to give strength or vigor" is from 1749. Related: Nerved; nerving.
Valencia: place in Spain, Roman Valentia Edetanorum "fort of the Edetani," a local people name; the first element from Latin valentia "strength" (see valence (n.)).
putt (v.): 1510s, Scottish, "to push, shove," a special use and pronunciation of put (v.). Golfing sense is from 1743. Meaning "to throw" (a stone, as a demonstration of strength) is from 1724; this also is the putt in shot putting. Related: Putted; putting.
pall (v.): "become tiresome," 1700, from Middle English pallen "to become faint, fail in strength" (late 14c.), shortened form of appallen "to dismay, fill with horror or disgust" (see appall). Related: Palled; palling.
re-enforce (v.): also reenforce, 1580s, "to give fresh strength to," from re- "back, again" + enforce (v.). Originally of persons or military units; of buildings, structures, etc., attested from 1883. Related: Re-enforced; re-enforcing.
belabor (v.): 1590s, "to exert one's strength upon," from be- + labor (v.). But figurative sense of "assail with words" is attested somewhat earlier (1590s); and belabored is attested from mid-15c. with a sense of "tilled, cultivated."
Alcestis: wife of Admetus, she offered her life for her husband and was rescued from the Underworld by Herakles, from Greek Alkestis, literally "valiant, courageous," from alke "protection, help, strength, power."
mensch (n.): "person of strength and honor," 1907, from Yiddish, from German Mensch, literally "man, person," from Old High German mennisco "human," from Proto-Germanic adjective *manniska- "human" (see mannish).
rigor (n.): late 14c., from Old French rigor "strength, hardness" (13c., Modern French rigueur), from Latin rigorem (nominative rigor) "numbness, stiffness, hardness, firmness; roughness, rudeness," from rigere "be stiff" (see rigid).
Bridget: fem. proper name, from Irish Brighid, fire goddess, from brigh "strength," from Celtic *brig-o-, from PIE *bhrgh-nt- "high, mighty," from root *bhrgh- "high" (see borough).
Zenobia: fem. proper name, from Greek Zenobia, literally "the force of Zeus," from Zen, collateral form of Zeus, + bia "strength, force," cognate with Sanskrit jya "force, power" (see Jain).
vehemence (n.): c. 1400, from Old French vehemence, veemence "forcefulness, violence, rashness" or directly from Latin vehementia "eagerness, strength," from stem of vehere (see vehement). Related: Vehemency.
ultra vires: Latin, literally "beyond powers," from ultra (see ultra-) + vires "strength, force, vigor, power," plural of vis (see vim). Usually "beyond the legal or constitutional power of a court, etc."
weedy (adj.): early 15c., from weed + -y (2). In old slang, in reference to horses, "not of good blood or strength, scraggy, worthless for breeding or racing," from 1800; hence, of persons, "thin and weakly" (1852).
exhaustion (n.): 1640s, "fatigue," noun of action from exhaust (v.) in sense of "drawing off" of strength. Etymological sense "act of drawing out or draining off" is from 1660s in English.
corrugated (adj.): 1620s, "wrinkled" (of skin, etc.), past participle adjective from corrugate. Meaning "bent into curves or folds" (of iron, cardboard, etc., for elasticity and strength) is from 1853.
enfeeble (v.): "to cause to weaken, deprive of strength," mid-14c., from Old French enfeblir "become weak," from en- (see en- (1)) + feble (see feeble). Related: Enfeebled; enfeebling; enfeeblement.
virility (n.): "period of manhood," 1580s, from Middle French virilité, from Latin virilitatem (nominative virilitas) "manhood," from virilis (see virile). Meaning "power of procreation, capacity for sexua intercourse" is from 1590s; sense of "manly strength" is recorded from c. 1600.
paresis (n.): "partial paralysis," 1690s, Modern Latin, from Greek paresis "letting go, slackening of strength, paralysis," from stem of parienai "to let go," from para- (see para- (1)) + hienai "to send, throw" (see jet (v.)).