infield (n.) Look up infield at
1733, "land of a farm which lies nearest the homestead," from in (adv.) + field (n.). Baseball diamond sense first attested 1866. Related: Infielder (1867).
infiltrate (v.) Look up infiltrate at
1758, of fluids, from in- (2) "in" + filtrate (v.). Perhaps modeled on French infiltrer (16c.). Military sense of "penetrate enemy lines" attested from 1934. Related: Infiltrated; infiltrating.
infiltration (n.) Look up infiltration at
"action or process of infiltrating," in physics, 1796, noun of action from infiltrate. Figurative sense of "a passing into" (anything immaterial) is from 1840; military sense of "stealthy penetration of enemy lines" dates from 1930. The same word had been used earlier in a medical sense of "a knitting together" (early 15c.), from Medieval Latin infiltratio.
infinite (adj.) Look up infinite at
late 14c., "eternal, limitless," also "extremely great in number," from Old French infinit "endless, boundless" and directly from Latin infinitus "unbounded, unlimited, countless, numberless," from in- "not, opposite of" (see in- (1)) + finitus "defining, definite," from finis "end" (see finish (v.)). The noun meaning "that which is infinite" is from 1580s.
infinitely (adv.) Look up infinitely at
early 15c., from infinite + -ly (2).
infinitesimal (adj.) Look up infinitesimal at
1710 (1650s as a noun), "infinitely small, less than any assignable quantity," from Modern Latin infinitesimus, from Latin infinitus "infinite" (see infinite) + ordinal word-forming element -esimus, as in centesimus "hundredth." Related: Infinitesimally.
infinitive (n.) Look up infinitive at
"simple, uninflected form of a verb, expressing its general sense," 1510s, from earlier use as an adjective (mid-15c.), from Late Latin infinitivus "unlimited, indefinite," from Latin infinitus "not limited" (see infinite). "Indefinite" because not restricted by person or number. Related: Infinitival; infinitively.
infinitude (n.) Look up infinitude at
1640s, from Medieval Latin *infinitudo, from Latin infinitus (see infinite) on model of multitudo, magnitudo. Or the English word is perhaps from or modeled on French infinitude (1610s).
infinity (n.) Look up infinity at
late 14c., from Old French infinité "infinity; very large number or quantity" (13c.), from Latin infinitatem (nominative infinitas) "boundlessness, endlessness," from infinitus boundless, unlimited" (see infinite). Latin infinitas was used as a loan-translation of Greek apeiria "infinity," from apeiros "endless."
infirm (adj.) Look up infirm at
late 14c., "weak, unsound" (of things), from Latin infirmus "weak, frail, feeble, not strong or firm" (figuratively "superstitious, pusillanimous, inconstant"), from in- "not, opposite of" (see in- (1)) + firmus "strong; stable," figuratively "constant, trusty" (see firm (adj.)). Of persons, "not strong, unhealthy," first recorded c. 1600. As a noun from 1711.
infirmary (n.) Look up infirmary at
mid-15c., "sick bay in a monastery," formerly also enfermerie, also firmary, fermery, from Old French enfermerie "hospital" and directly from Medieval Latin infirmaria "a place for the infirm," from Latin infirmus "weak, frail," (see infirm). According to OED, the common name for a public hospital in 18c. England.
infirmity (n.) Look up infirmity at
late 14c., "disease, sickness; lack of capability, weakness," from Latin infirmitatem (nominative infirmitas) "want of strength, weakness, feebleness," also "the weaker sex" [Lewis], noun of quality from infirmus "weak, frail" (see infirm). Perhaps in part from Middle French infirmité, Old French enfermete "illness, sickness, disease; moral weakness."
inflame (v.) Look up inflame at
mid-14c., "make (someone) ardent; set (the spirit, etc.) on fire" with a passion or religious virtue, a figurative sense, from Old French enflamer "catch fire; set on fire" (Modern French enflammer), from Latin inflammare "to set on fire, kindle," figuratively "to rouse, excite," from in- "in" (see in- (2)) + flammare "to flame," from flamma "a flame" (see flame (n.)).

The literal sense of "to cause to burn" first recorded in English late 14c. Meaning "to heat, make hot, cause inflammation" is from 1520s. Formerly also enflame, but since 16c. the spelling with in- has predominated. Related: Inflamed; Inflaming.
inflammable (adj.) Look up inflammable at
"able to be set alight," c. 1600, from Middle French inflammable, from Medieval Latin inflammabilis, from Latin inflammare "to set on fire" (see inflame).Since 1980s use of the word, especially in safety warnings, has been sometimes discouraged for fear it could be misunderstood as meaning "non-flammable" through confusion of the two prefixes in-. The word was used earlier in medicine in the sense "liable to inflammation" (early 15c.). Related: Inflammability.
inflammation (n.) Look up inflammation at
early 15c., in pathology, "excessive redness or swelling in a body part," from Old French inflammation (14c.) and directly from Latin inflammationem (nominative inflammatio) "a kindling, a setting on fire," noun of action from past participle stem of inflammare "to set on fire" (see inflame). Literal sense "act of setting on fire" in English is from 1560s.
inflammatory (adj.) Look up inflammatory at
"tending to rouse passions or desires," 1711, a figurative use from Latin inflammat-, past participle stem of inflammare "to set on fire" (see inflame) + -ory. From 1732 in pathology, "accompanied by (pathological) inflammation." as a noun from 1680s.
inflatable (adj.) Look up inflatable at
1821, from inflate + -able.
inflate (v.) Look up inflate at
early 15c., "cause to swell," from Latin inflatus (source also of Italian enfiare, Spanish inflar, French enfler), past participle of inflare "to blow into, inflate" (see inflation). Economics sense (of prices, currency, etc.) is from 1843. In some senses a back-formation from inflation. Related: Inflated; inflating.
inflation (n.) Look up inflation at
mid-14c., "swelling caused by gathering of 'wind' in the body; flatulence," also, figuratively, "outbursts of pride," from Latin inflationem (nominative inflatio) "a puffing up, a blowing into; flatulence," noun of action from past participle stem of inflare "blow into, puff up," figuratively "inspire, encourage," from in- "into" (see in- (2)) + flare "to blow" (see blow (v.1)).

Meaning "action of inflating with air or gas" is from c. 1600. Monetary sense of "enlargement of prices" (originally by an increase in the amount of money in circulation) first recorded 1838 in American English.
inflationary (adj.) Look up inflationary at
1916, from inflation + -ary.
inflect (v.) Look up inflect at
early 15c., "to bend inward," from Latin inflectere (past participle inflexus) "to bend in, bow, curve," figuratively, "to change, alter, influence," from in- "in" (see in- (1)) + flectere "to bend" (see flexible). Grammatical sense "to vary by change of form" (especially at the end of a word) is fromd 1660s. Related: Inflected; inflecting.
inflected (adj.) Look up inflected at
1640s, "bent, curved," past-participle adjective from inflect (v.). Grammatical sense is from 1775.
inflection (n.) Look up inflection at
also inflexion, early 15c., from Middle French inflexion and directly from Latin inflexionem (nominative inflexio) "a bending, inflection, modification," noun of action from past participle stem of inflectere "to bend in, to change" (see inflect). For spelling, see connection. Grammatical sense "variation by declension or conjugation" is from 1660s; pronunciation sense "modulation of the voice" is from c. 1600.
inflexibility (n.) Look up inflexibility at
1610s, from inflexible + -ity.
inflexible (adj.) Look up inflexible at
late 14c., "incapable of being bent, physically rigid," also figuratively, "unyielding in temper or purpose," from Middle French inflexible and directly from Latin inflexibilis "that cannot be bent," from in- "not, opposite of" (see in- (1) + flexibilis "pliant, yielding" (see flexible). In early 15c. an identical word had an opposite sense, "capable of being swayed or moved," from in- "in, on." Related: Inflexibly.
inflexion (n.) Look up inflexion at
see inflection; also see -xion. Related: Inflexional.
inflict (v.) Look up inflict at
1560s, "assail, trouble;" 1590s, "lay or impose as something that must be suffered," from Latin inflictus, past participle of infligere "to strike or dash against; inflict," from in- "in" (see in- (2)) + fligere (past participle flictus) "to dash, strike" (see afflict). You inflict trouble on someone; you afflict someone with trouble. Shame on you.
infliction (n.) Look up infliction at
1530s, "act of inflicting;" 1580s, "that which is inflicted," from Middle French infliction (15c.), or directly from Late Latin inflictionem (nominative inflictio) "an inflicting, a striking against," noun of action from past participle stem of Latin infligere "to strike or dash against" (see inflict).
inflorescence (n.) Look up inflorescence at
1760, "arrangement of flowers on a stem in relation to one another," from Modern Latin inflorescentia, from Late Latin inflorescentem (nominative inflorescens) "flowering," present participle of Latin inflorescere "to come to flower," from in- "in" (see in- (2)) + florescere "to begin to bloom" (see flourish (v.)). Meaning "a beginning to bloom" in English is from 1800.
inflow (n.) Look up inflow at
1839, from in (adj.) + flow (n.).
influence (n.) Look up influence at
late 14c., an astrological term, "streaming ethereal power from the stars when in certain positions, acting upon character or destiny of men," from Old French influence "emanation from the stars that acts upon one's character and destiny" (13c.), also "a flow of water, a flowing in," from Medieval Latin influentia "a flowing in" (also used in the astrological sense), from Latin influentem (nominative influens), present participle of influere "to flow into, stream in, pour in," from in- "into, in, on, upon" (see in- (2)) + fluere "to flow" (see fluent).

The range of senses in Middle English were non-personal, in reference to any outflowing of energy that produces effect, of fluid or vaporous substance as well as immaterial or unobservable forces. Meaning "exertion of unseen influence by persons" is from 1580s (a sense already in Medieval Latin, for instance Aquinas); meaning "capacity for producing effects by insensible or invisible means" is from 1650s. Under the influence (of alcohol, etc.) "drunk" first attested 1866.
influence (v.) Look up influence at
1650s, from influence (n.). Related: Influenced; influencing.
influent (adj.) Look up influent at
mid-15c., "abundant, flowing in," in reference to occult power of the stars, etc., also of grace, from Latin influentem (nominative influens) "flowing in," present participle of influere "to flow in" (see influence (n.)). Also occasionally in the sense "influential" (1630s).
influential (adj.) Look up influential at
"powerful, having influence," 1650s, from Medieval Latin influentialis, from influentia (see influence (n.)). Earlier in an astrological sense (1560s). Related: Influentially.
influenza (n.) Look up influenza at
1743, borrowed (during an outbreak of the disease in Europe), from Italian influenza "influenza, epidemic," originally "visitation, influence (of the stars)," from Medieval Latin influentia in the astrological sense (see influence).

Used in Italian for diseases since at least 1504 (as in influenza di febbre scarlattina "scarlet fever") on notion of astral, occult, or atmospheric influence. The 1743 outbreak began in Italy. Often applied since mid-19c. to severe colds.
influx (n.) Look up influx at
1620s, from French influx (16c.) or directly from Late Latin influxus "a flowing in," from past participle stem of Latin influere "to flow in" (see influence (n.)). Originally of rivers, air, light, spiritual light, etc.; used of people from 1650s.
info (n.) Look up info at
1906, short for information.
info- Look up info- at
word-forming element abstracted from information.
infold (n.) Look up infold at
see enfold. Related: Infolded; infolding.
infomercial (n.) Look up infomercial at
1983, from info- + commercial (n.). Before the televised infomercial was the newspaper advertorial (1961).
inform (v.) Look up inform at
early 14c., "to train or instruct in some specific subject," from Old French informer, enformer "instruct, teach" (13c.) and directly from Latin informare "to shape, give form to, delineate," figuratively "train, instruct, educate," from in- "into" (see in- (2)) + formare "to form, shape," from forma "form" (see form (n.)). In early use also enform until c. 1600. Sense of "report facts or news, communicate information to" first recorded late 14c. Related: Informed; informing.
informal (adj.) Look up informal at
mid-15c., "lacking form; not in accordance with the rules of formal logic," from in- (1) "not, opposite of" + formal (adj.). Meaning "irregular, unofficial, not according to rule or custom" is from c. 1600. Sense of "done without ceremony" is from 1828. Related: Informally.
informality (n.) Look up informality at
1590s, from informal + -ity.
informant (n.) Look up informant at
1690s, "someone who supplies information," from Latin informantem (nominative informans), present participle of informare "train, instruct, educate" (see inform). Occasionally as "one who gives information to the authorities, one who dishonorably betrays knowledge gained in confidence" (1783). Informer is older in both senses and more usual in the latter. As an adjective from 1890.
informatics (n.) Look up informatics at
1967, translating Russian informatika (1966); see information + -ics.
information (n.) Look up information at
late 14c., informacion, "act of informing, communication of news," from Old French informacion, enformacion "advice, instruction," from Latin informationem (nominative informatio) "outline, concept, idea," noun of action from past participle stem of informare "to train, instruct, educate; shape, give form to" (see inform). The restored Latin spelling is from 16c.

Meaning "knowledge communicated concerning a particular topic" is from mid-15c. The word was used in reference to television broadcast signals from 1937; to punch-card operating systems from 1944; to DNA from 1953. Information theory is from 1950; information technology is from 1958 (coined in "Harvard Business Review"); information revolution, to be brought about by advances in computing, is from 1966. Information overload is by 1967.
informational (adj.) Look up informational at
1810, from information + -al (1).
informative (adj.) Look up informative at
1650s, "instructive, didactic," from Medieval Latin informativus, from Latin informatus, past participle of informare "to train, instruct, educate" (see inform). In Middle English, the same word meant "formative, shaping, plastic, having power to form or animate" (late 14c.). Related: Informatively.
informed (adj.) Look up informed at
1540s, "current in information," past-participle adjective from inform (v.). In 16c.-17c. it also could mean "unformed, formless," from in- (1) "not, opposite of," and was used in astronomy of stars that did not form part of the visual pattern of a constellation but were within it.
informer (n.) Look up informer at
late 14c., enfourmer "instructor, one who teaches or gives advice," from inform (Middle English enfourmen) and also from Old French enformeor. Meaning "one who communicates information" is mid-15c.; sense of "one who gives information against another" (especially in reference to law-breaking) is c. 1500.