inductive (adj.) Look up inductive at Dictionary.com
early 15c., from Old French inductif or directly from Late Latin inductivus, from induct-, past participle stem of inducere (see induce). As a term in logic, from 1764.
inductor (n.) Look up inductor at Dictionary.com
1650s, from Latin inductor, agent noun from past participle stem of inducere (see induce). Electromagnetic sense begins in 1837.
indulge (v.) Look up indulge at Dictionary.com
1630s, "to grant as a favor;" 1650s, of both persons and desires, "to treat with unearned favor;" a back-formation from indulgence, or else from Latin indulgere "to be complaisant." Related: Indulged; indulging.
indulgence (n.) Look up indulgence at Dictionary.com
mid-14c., "freeing from temporal punishment for sin," from Old French indulgence or directly from Latin indulgentia "complaisance, fondness, remission," from indulgentem (nominative indulgens) "indulgent, kind, tender, fond," present participle of indulgere "be kind, yield," of unknown origin; perhaps from in- "in" + derivative of PIE root *dlegh- "to engage oneself."

Sense of "gratification of another's desire or humor" is attested from late 14c. That of "yielding to one's inclinations" (technically self-indulgence) is from 1640s. In British history, Indulgence also refers to grants of certain liberties to Nonconformists under Charles II and James II, as special favors rather than legal rights; specifically the Declarations of Indulgence of 1672, 1687, and 1688 in England and 1669, 1672, and 1687 in Scotland.
indulgent (adj.) Look up indulgent at Dictionary.com
c.1500, from Latin indulgentem (nominative indulgens), present participle of indulgere (see indulgence). Related: Indulgently.
indurate (v.) Look up indurate at Dictionary.com
1530s, from Latin induratus, past participle of indurare "to make hard, harden" (see endure). Related: Indurated.
induration (n.) Look up induration at Dictionary.com
late 14c., from Old French induracion "hardness, obstinacy" (14c.) or directly from Medieval Latin indurationem (nominative induratio) "hardness (especially of the heart)," noun of action from indurare (see endure).
Indus Look up Indus at Dictionary.com
river in Asia, from Sanskrit sindhu "river." The southern constellation, created 1603 by Bayer, represents "an Indian," not the river.
industrial (adj.) Look up industrial at Dictionary.com
1774, from French industriel, from Medieval Latin industrialis, from Latin industria (see industry). Earlier the word had been used in English in a sense "resulting from labor" (1580s); the modern use is considered a reborrowing. Meaning "suitable for industrial use" is from 1904. As a style of dance music, attested from 1988. Industrial revolution was in use by 1840 to refer to recent developments and changes in England and elsewhere.
industrialisation (n.) Look up industrialisation at Dictionary.com
chiefly British English spelling of industrialization (q.v.); for spelling, see -ize.
industrialism (n.) Look up industrialism at Dictionary.com
1831, from industrial + -ism. Compare French industrialisme (Saint-Simon, 1823).
industrialist (n.) Look up industrialist at Dictionary.com
1846, from industrial + -ist. Perhaps modeled on French industrialiste (Saint-Simon, 1823). Earlier "one who makes a living by productive industry" (1837).
industrialization (n.) Look up industrialization at Dictionary.com
1883, from industrialize + -ation.
industrialize (v.) Look up industrialize at Dictionary.com
1852, from industrial + -ize, or else from French industrialiser (1842), from Medieval Latin industrialis. Related: Industrialized; industrializing.
industrious (adj.) Look up industrious at Dictionary.com
"characterized by energy, effort, and attention," 1520s (implied in industriously), from Middle French industrieux and directly from Late Latin industriosus, from Latin industria (see industry). Retains the etymological sense. Related: Industriousness.
industry (n.) Look up industry at Dictionary.com
late 15c., "cleverness, skill," from Old French industrie "activity; aptitude" (14c.) or directly from Latin industria "diligence, activity, zeal," fem. of industrius "industrious, diligent," used as a noun, from early Latin indostruus "diligent," from indu "in, within" + stem of struere "to build" (see structure (n.)). Sense of "diligence, effort" is from 1530s; meaning "trade or manufacture" first recorded 1560s; that of "systematic work" is 1610s.
indwelling (n.) Look up indwelling at Dictionary.com
"act of residing," late 14c. (Wyclif's translation of Latin inhabitatio), present participle of obsolete indwell, from in (adv.) + dwell (v.). He also used indweller for Latin inhabitans.
inebriate (v.) Look up inebriate at Dictionary.com
late 15c., from Latin inebriatus, past participle of inebriare "to make drunk," from in- "in" (see in- (2)) + ebriare "make drunk," from ebrius "drunk," of unknown origin. Related: Inebriated; inebriating. Also inebriacy; inebriant (n. and adj.); inebriety; and inebrious.
inebriated (adj.) Look up inebriated at Dictionary.com
"drunken," c.1600, past participle adjective from inebriate.
inebriation (n.) Look up inebriation at Dictionary.com
1520s, from Late Latin inebriationem (nominative inebriatio), noun of action from past participle stem of inebriare (see inebriate).
inedible (adj.) Look up inedible at Dictionary.com
"unfit to eat," 1822, from in- (1) "not, opposite of" + edible. Related: Inedibly; inedibility.
ineducable (adj.) Look up ineducable at Dictionary.com
1884, from in- (1) "not" + educable. Related: Ineducability.
ineffability (n.) Look up ineffability at Dictionary.com
1620s; see ineffable + -ity.
ineffable (adj.) Look up ineffable at Dictionary.com
late 14c., from Old French ineffable (14c.) or directly from Latin ineffabilis "unutterable," from in- "not, opposite of" (see in- (1)) + effabilis "speakable," from effari "utter," from ex- "out" (see ex-) + fari "speak" (see fame (n.)). Plural noun ineffables was, for a time, a jocular euphemism for "trousers" (1823). Related: Ineffably.
ineffective (adj.) Look up ineffective at Dictionary.com
1650s, from in- (1) "not, opposite of" + effective. Related: Ineffectively; ineffectiveness.
ineffectual (adj.) Look up ineffectual at Dictionary.com
early 15c., from in- (1) "not, opposite of" + effectual. Related: Ineffectually; ineffectuality.
inefficacious (adj.) Look up inefficacious at Dictionary.com
1650s, from in- (1) "not, opposite of" + efficacious. Related: Inefficaciously; inefficaciousness (1640s).
inefficacy (n.) Look up inefficacy at Dictionary.com
"want of force or virtue to produce the desired effect," 1610s, from Late Latin inefficacia, from inefficacem (nominative inefficax), from in- "not, opposite of" (see in- (1)) + efficax (see efficacy).
inefficient (adj.) Look up inefficient at Dictionary.com
1750, "not producing the desired effect," from in- (1) "not, opposite of" + efficient. Related: Inefficiency (1749); inefficiently.
inelastic (adj.) Look up inelastic at Dictionary.com
1748, from in- (1) "not, opposite of" + elastic. Figurative use attested by 1867.
inelegant (adj.) Look up inelegant at Dictionary.com
c.1500, from French inélégant (15c.), from Latin inelegantem (nominative inelegans) "not choice, without taste, without judgment," from in- "not" (see in- (1)) + elegans (see elegant). Related: Inelegantly; inelegance.
ineligible (adj.) Look up ineligible at Dictionary.com
1770, from in- (1) "not, opposite of" + eligible.
ineluctable (adj.) Look up ineluctable at Dictionary.com
"not to be escaped by struggling," 1620s, from Latin ineluctabilis "unavoidable, inevitable," from in- "not, opposite of" (see in- (1)) + eluctari "to struggle out of," from ex- "out" (see ex-) + luctari "to struggle" (see reluctance).
inept (adj.) Look up inept at Dictionary.com
c.1600, from Old French inepte (14c.) or directly from Latin ineptus "unsuitable, improper, absurd, awkward, silly, tactless," from in- "not, opposite of" (see in- (1)) + aptus "apt" (see apt). Related: Ineptly; ineptness.
ineptitude (n.) Look up ineptitude at Dictionary.com
1610s, from French ineptitude, from Latin ineptitudo, noun of quality from ineptus "unsuitable, absurd" (see inept).
inequable (adj.) Look up inequable at Dictionary.com
1717, from Latin inaequabilis "uneven," from in- "not" (see in- (1)) + aequabilis (see equable).
inequality (n.) Look up inequality at Dictionary.com
early 15c., "difference of rank or dignity," from Old French inequalité (14c.) and directly from Medieval Latin inaequalitas, from Latin inaequalis "unequal," from in- "not, opposite of" (see in- (1)) + aequalis "equal" (see equal).
inequitable (adj.) Look up inequitable at Dictionary.com
1660s, from in- (1) "not, opposite of" + equitable. Related: Inequitably.
inequity (n.) Look up inequity at Dictionary.com
1550s, from in- (1) "not, opposite of" + equity. Formed from the same elements as iniquity, but natively. Related: Inequities.
ineradicable (adj.) Look up ineradicable at Dictionary.com
1794, from in- (1) "not, opposite of" + eradicable (see eradicate). Related: Ineradicably.
inerrancy (n.) Look up inerrancy at Dictionary.com
1818, from inerrant + -cy.
inerrant (adj.) Look up inerrant at Dictionary.com
1650s, in reference to "fixed" stars (as opposed to "wandering" planets), from Latin inerrantem (nominative inerrans) "not wandering," from in- "not, opposite of" (see in- (1)) + errans, present participle of errare "to err" (see err).
inert (adj.) Look up inert at Dictionary.com
1640s, from French inerte (16c.) or directly from Latin inertem (nominative iners) "unskilled, inactive, helpless, sluggish, worthless," from in- "without" + ars (genitive artis) "skill" (see art (n.)). Originally of matter; specifically of gases from 1885. Of persons or creatures, from 1774.
inertia (n.) Look up inertia at Dictionary.com
1713, introduced as a term in physics 17c. by German astronomer and physician Johann Kepler (1571-1630), from Latin inertia "unskillfulness, idleness," from iners (genitive inertis) "unskilled, inactive;" see inert. Used in Modern Latin by Newton (1687). Sense of "apathy" first recorded 1822.
inertial (adj.) Look up inertial at Dictionary.com
1737, from inertia + -al (1).
inertness (n.) Look up inertness at Dictionary.com
1660s, from inert + -ness.
inescapable (adj.) Look up inescapable at Dictionary.com
1792, from in- (1) "not, opposite of" + escapable (see escape). Related: Inescapably.
inestimable (adj.) Look up inestimable at Dictionary.com
late 14c., "beyond estimation," from Old French inestimable (14c.) or directly from Latin inaestimabilis, from in- "not, opposite of" (see in- (1)) + aestimabilis (see estimable). Meaning "too precious to set a value on, priceless" is attested by 1570s. Related: Inestimably.
inevitability (n.) Look up inevitability at Dictionary.com
1640s, from inevitable + -ity.
inevitable (adj.) Look up inevitable at Dictionary.com
mid-15c., from Latin inevitabilis "unavoidable," from in- "not, opposite of" (see in- (1)) + evitabilis "avoidable," from evitare "to avoid," from ex- "out" (see ex-) + vitare "shun," originally "go out of the way."