isolation (n.)
1800, noun of action from isolate (v.) or else from French isolation, noun of action from isoler (see isolated).
isolationist (n.)
1899 in reference to U.S. foreign policy, "one who advocates a policy of non-participation in foreign affairs" (earlier in reference to treatment of leprosy), from isolation + -ist. As an adjective from 1920. Isolationism is attested in a general sense by 1902; in a U.S. geopolitical sense from 1922.
Isold
fem. proper name, French Isolt, Iseut, of Germanic origin, literally "ice-rule," from Proto-Germanic *is "ice" (see ice (n.)) + *waldan "to rule" (from PIE root *wal- "to be strong").
isomer (n.)
1852, in chemistry, back-formation from isomeric. A compound identical or nearly so in composition and molecular weight with another, but having different properties.
isomeric (adj.)
"pertaining to or characterized by isomerism," 1831, from German isomerisch (Berzelius, 1831, in a paper on the "Composition of the Tartaric and Paratartaric Racemic Acids"), from Greek isomeres "sharing equality, having equal parts or shares," from iso- "equal" (see iso-) + meros "part, share" (see merit (n.)). Isomerous is from 1845 in botany, 1840 in chemistry.
isometric (adj.)
1838, literally "of the same measure," from iso- "the same, equal" + -metric. The components are Greek: isos "equal, identical" + metron "a measure." Originally a method of using perspective in drawing; later in reference to crystals. The physiological sense relating to muscular action is from 1889, from German isometrisch in this sense (1882).
isometrics (n.)
as a type of exercise, 1962, American English, from isometric; also see -ics.
isometry (n.)
in mathematics, 1941, probably from isometric (q.v.) on the model of geometry/geometric.
isomorph (n.)
"that which has the same form as another but belongs to a different group," 1850 of mineral substances; 1885 in zoology, probably a back-formation from isomorphism (q.v.), but used earlier in German (1821)..
isomorphic (adj.)
"the same in form, alike," 1862 [Robert Gordon Latham, "Elements of Comparative Philology"], from iso- "equal, identical" + -morphic, from Greek morphe "form, shape" (see Morpheus). Earlier adjective was isomorphous (1821).
isomorphism (n.)
"similarity of form," 1822, in John George Children's translation from French of Berzelius's "The Use of the Blow-pipe in Chemical Analysis," from French l'isomorphisme, from German Isomorphismus (1819), coined by German chemist Eilhard Mitscherlich (1794-1863) from Greek isos "equal, identical" (see iso-) + morphe "form, appearance" (see Morpheus).
Mr. Children has, very properly in our estimation, wholly omitted the formulae, translating them into plain English in notes at the bottom of the page; we wish he had exerted the same discretionary judgment with respect to the isomorphisms and left them out likewise. [from a review of Children's book in "The Quarterly Review of Science, Literature, and the Arts," vol. xiii, 1822]
isonomia (n.)
"equality before the law," c. 1600, from Italian or Latin, ultimately from Greek isonomia "equality of rights, the equality of a Greek democracy," from isos "equal, identical" (see iso-) + nomos "law" (see numismatics). Related: Isonomic (1851), which appears to be a separate formation in geology. Greek also had isoteleia in reference to an equality before the law sometimes granted to aliens in Athens, "equality of tax and tribute."
isopod (n.)
"animal with legs equal in size and position," 1835, from French isopode, from Latin isopoda (neuter plural), from Greek iso- "equal, identical" (see iso-) + pod-, stem of pous "foot" (from PIE root *ped- "foot").
isopolity (n.)
"equality of citizenship rights between different states," 1827, in reference to ancient Rome, from iso- "equal, identical" + polity.
isosceles (adj.)
"having two equal sides," 1550s, from Late Latin isosceles, from Greek isoskeles "with equal legs; isosceles; that can be divided into two equal parts," from isos "equal, identical" (see iso-) + skelos "leg," from PIE *skel-es-, from root *(s)kel- (3) "crooked" (see scoliosis).
isostasy (n.)
"equilibrium from equality of pressure," 1889 (C.E. Dutton), from iso- + Greek stasis "setting, weighing, standing" (see stasis). Greek isostasios meant "in equipoise with, equivalent to."
isostatic (adj.)
"in equilibrium from equality of pressure," 1889, from isostasy + -ic.
isotherm (n.)
"line connecting points on the earth having the same mean temperature," 1850, from French isotherme (von Humboldt, 1817), from Greek isos "equal, identical" (see iso-) + therme "heat" (see thermal (adj.)).
isothermal (adj.)
1816, literally "of equal heat," from French isotherme (see isotherm) + -al (1). As a noun, "isothermal line," from 1849.
isotonic (adj.)
"having or indicating equal tones," 1776, from Greek isotonos "of level pitch; equally stretched," from iso- "equal, identical" (see iso-) + tonos "tone," from PIE root *ten- "to stretch."
isotope (n.)
1913, literally "having the same place," from Greek isos "equal" (see iso-) + topos "place" (see topos); so called because, despite having different atomic weights, the various forms of an element occupy the same place on the periodic table. Introduced by British chemist Frederick Soddy (1877-1956) on suggestion of his friend, the Scottish writer and doctor Margaret Todd (c. 1859-1918). Related: Isotopic.
isotropic (adj.)
"having the same properties in all directions," 1856, from iso- + -tropic, from Greek tropikos "belonging to a turning," from tropos "a turning, way, manner," from trepein "to turn" (from PIE root *trep- "to turn"). Isotropous is from 1859.
Israel
Old English Israel, "the Jewish people, the Hebrew nation," from Latin Israel, from Greek, from Hebrew yisra'el "he that striveth with God" (Genesis xxxii.28), symbolic proper name conferred on Jacob and extended to his descendants, from sara "he fought, contended" + El "God." As the name of an independent Jewish state in the Middle East, it is attested from 1948. Compare Israeli, Israelite.
Israeli (n.)
"citizen of the state of Israel," 1948, from Israel + Hebrew national designation suffix -i. Also used in English as the adjective (1948). It distinguishes the citizens of the modern state from the ancient people who had been known in English since 14c. as Israelites (see Israelite).
Israelite (n.)
mid-14c., "a Jew; one of the people of ancient Israel, a descendant of Israel or Jacob," from Latin israelita, from Greek Israelites, from Israel (see Israel). The Middle English adjective was Israelish (Old English Israelisc), sometimes Israelitish (Coverdale, 1530s); Israelitic (c. 1600, from Late Latin Israeliticus).
Issachar
son of Jacob by Leah (Old Testament) and name of a biblical tribe of Israel, from Greek issakhar, from Hebrew Yissakhar, probably [Klein] from Hebrew yesh sakhar "there is a reward" (see Genesis xxx.18).
Issei (n.)
c. 1930s, collective term used among Japanese in U.S. for first-generation immigrants, in Japanese literally "first generation," related to ichi "one."
issuable (adj.)
1560s, from issue (v.) + -able. Related: Issuably.
issuance (n.)
"act of issuing," 1823, American English, from issue (v.) + -ance.
issue (v.)
mid-14c., of water, etc., "to flow out;" of persons, "come or go (out of a place), sally forth," from issue (n.) or else from Old French issu, past participle of issir. Transitive sense of "to send out" is from mid-15c.; specific sense of "to send out authoritatively" is from c. 1600. Meaning "supply (someone with something)" is from 1925. Related: Issued; issuing.
issue (n.)
c. 1300, "an exit," from Old French issue "a way out, a going out, exit; final event," from fem. past participle of issir "to go out," from Latin exire "go out, go forth; become public; flow, gush, pour forth" (source also of Italian uscire, Catalan exir), from ex- "out" (see ex-) + ire "to go," from PIE root *ei- "to go."

Meaning "discharge of blood or other fluid from the body" is from 1520s; sense of "offspring, children" is from late 14c. Meaning "outcome of an action, consequence, result" is attested from late 14c., probably from this sense in French. Meaning "action of sending into publication or circulation" is from 1833.

Legal sense developed from the notion of "end or result of pleadings in a suit (by presentation of the point to be determined by trial)," hence "the controversy over facts in a trial" (early 14c., Anglo-French) and transferred sense "point of contention between two parties" (early 15c.) and the general sense "an important point to be decided" (1836). Hence also the verbal phrase take issue with (1797, earlier join issue, 1690s) "take up an affirmative or negative position in a dispute with another." To have issues "have unresolved conflicts" is by 1990.
Istanbul
Turkish name of Constantinople; it developed in Turkish 16c. as a corruption of Greek phrase eis tan (ten) polin "in (or to) the city," which is how the local Greek population referred to it. Turkish folk etymology traces the name to Islam bol "plenty of Islam." Greek polis "city" has been adopted into Turkish as a place-name suffix -bolu.
isthmian (adj.)
c. 1600, from Latin isthmius, from Greek isthmios "pertaining to the isthmus (of Corinth)," from isthmos (see isthmus). Originally in reference to the Isthmian Games, held at Corinth in honor of Poseidon.
isthmus (n.)
1550s, from Latin isthmus, from Greek isthmos "narrow passage, narrow neck of land between two seas," originally especially that of Corinth, a word of unknown origin. Perhaps from eimi "to go" + suffix -thmo (compare ithma "a step, movement").
Istria
peninsula near the head of the Adriatic Sea, Latin Istria, from Istaevones, name of a Germanic people there, of unknown origin. Related: Istrian (c. 1600).
it (pron.)
Old English hit, neuter nominative and accusative of third person singular pronoun, from Proto-Germanic demonstrative base *khi- (source also of Old Frisian hit, Dutch het, Gothic hita "it"), from PIE *ko- "this" (see he). Used in place of any neuter noun, hence, as gender faded in Middle English, it took on the meaning "thing or animal spoken about before."

The h- was lost due to being in an unemphasized position, as in modern speech the h- in "give it to him," "ask her," is heard only "in the careful speech of the partially educated" [Weekley]. It "the sex act" is from 1610s; meaning "sex appeal (especially in a woman)" first attested 1904 in works of Rudyard Kipling, popularized 1927 as title of a book by Elinor Glyn, and by application of It Girl to silent-film star Clara Bow (1905-1965). In children's games, the meaning "the one who must tag or catch the others" is attested from 1842.

From Old English as nominative of an impersonal verb or statement when the thing for which it stands is implied (it rains, it pleases me). After an intransitive verb, used transitively for the action denoted, from 1540s (originally in fight it out). That's it "there is no more" is from 1966; this is it "the anticipated or dreaded moment has arrived" is from 1942.
Italian (n.)
early 15c., "native of Italy," from Italian Italiano, from Italia "Italy" (see Italy). Meaning "the Italian language" is late 14c. As an adjective from 1510s. Earlier the Italians were the Italies (late 14c.).
Italianate (adj.)
1570s, from Italian Italianato "rendered Italian," from Italiano (see Italian). In older use "applied especially to fantastic affectations of fashions borrowed from Italy" [Century Dictionary], or in reference to the supposed Italian proverb that translates as an Englishman Italianate is a Devil incarnate which circulated in English (there also was a version in Germany about Italianized Germans).
Italianism (n.)
1590s, from Italian + -ism.
italic (adj.)
"type of printing with lines sloping to the right," 1610s, from Latin italicus "Italian, of Italy," from Italia (see Italy). So called because it was introduced in 1501 by Aldus Manutius, printer of Venice (who also gave his name to Aldine), and first used in his edition of Virgil, which was dedicated to Italy. As a noun, "italic type," 1670s.
[Italics] pull up the reader and tell him not to read heedlessly on, or he will miss some peculiarity in the italicized word. [Fowler]
Earlier (1570s) the word was used in English for the plain, sloping style of handwriting (opposed to gothic), and italic printing sometimes in English was called cursive (and also Aldine). Often, but not always, for emphasis; in manuscripts indicated by an underscored line. Related: Italics.
The Italic words in the Old and New Testament are those, which have no corresponding words in the original Hebrew or Greek; but are added by the translators, to complete or explain the sense. [Joseph Robertson, "An Essay on Punctuation," 1785]
Italic (adj.)
"of or pertaining to ancient Italy," 1680s, from Latin Italicus, from Italia (see Italy). A word of historians and antiquarians. Earlier in the sense "pertaining to the Greek colonies in southern Italy" (1660s) and as the name of one of the orders of classical architecture (1560s).
italicize (v.)
"to print in italics" (for emphasis, etc.), 1795, from italic + -ize. Related: Italicized; italicizing; italicization.
Italiot (adj.)
also Italiote, of or belonging to the ancient Greek settlements in southern Italy," 1650s, from Greek Italiotes, from Italia (see Italy).
Italy
from Latin Italia, from Greek Italia; of unknown origin. Perhaps an alteration of Oscan Viteliu "Italy," but meaning originally only the southwestern point of the peninsula. Traditionally said to be from Vitali, name of a tribe that settled in Calabria, whose name is perhaps somehow connected with Latin vitulus "calf." Or perhaps the country name is directly from vitulus as "land of cattle," or it might be from an Illyrian word, or an ancient or legendary ruler Italus. The modern nation dates from events of 1859-60 and was completed by the addition of Venetia in 1866 and Rome in 1870.
itch (n.)
"irritating tingling sensation in the skin," also "skin inflammation caused by a burrowing mite," Old English gicce, from giccan (v.) "to itch" (see itch (v.)). Sense of "restless desire" is first attested 1530s; itching in this sense is from mid-14c.
itch (v.)
Middle English icchen, from Old English giccan "to itch," from West Germanic *jukkjan (source also of Middle Dutch jöken "to itch," Old High German jucchen, German jucken). Figurative sense of "feel a provoking desire to do or get something" is from early 13c. Related: Itched; itching.
itchy (adj.)
Old English giccig; see itch + -y (2). Figurative itchy palm is attested by 1599 (Jonson; Shakespeare has itching palm in the same sense, 1601). Other figurative uses include itching ears "a hankering for gossip," itching elbows "a passion for gambling." Related: Itchiness.
item (n.)
late 14c., originally an adverb, "moreover, in addition," from Latin item (adv.) "likewise, just so, moreover," probably from ita "thus," id "it" (see id) + adverbial ending -tem (compare idem "the same").

The Latin adverb was used to introduce a new fact or statement, and in French and English it was used before every article in an enumeration (such as an inventory or bill). This practice led to the noun sense "an article of any kind" (1570s). Meaning "detail of information" (especially in a newspaper) is from 1819; item "sexually linked unmarried couple" is 1970, probably from notion of being an item in the gossip columns.
itemize (v.)
1833 (implied in itemized), American English, from item + -ize. Related: Itemizing. An earlier verb was item "make a note of" (c. 1600).
iterate (v.)
1530s, "to do again, repeat," back-formation from iteration, or else from Latin iteratus, past participle of iterare "do again, repeat." Related: Iterated; iterating.