Online Etymology Dictionary

interoffice (adj.): also inter-office, 1864, from inter- "between" + office (n.).
interoperable (adj.): 1969, from inter- "between" + operable. Related: Interoperability.
interphase (n.): in cytology, 1913, from German interphase (1912); see inter- "between" + phase (n.).
interpolation (n.): 1610s, "act of interpolating;" 1670s, "that which is interpolated," from French interpolation (17c.) or directly from Latin interpolationem (nominative interpolatio), noun of action from past participle stem of interpolare "to alter; falsify" (see interpolate).
interracial (adj.): also inter-racial, "existing or taking place between races," 1883, from inter- "between" + racial (adj.).
interrelate (v.): also inter-relate, 1831 (implied in interrelated), transitive, "bring into reciprocal relation," from inter- "between" + relate (v.). Intransitive sense "come into reciprocal relation" is attested from 1912. Related: Interrelating.
interrelation (n.): 1841, from inter- "between" + relation.
interrelationship (n.): also inter-relationship, "state of being interrelated," 1841, from inter- "between" + relationship.
interpellate (v.): 1590s, "interrupt," from Latin interpellatus, past participle of interpellare "to interrupt by speaking" (see interpellation). Parliamentary sense of "question formally or publically" is from 1874, from French. Related: Interpellated; interpellating.
interpellation (n.): late 15c., "an appeal" (obsolete), from Latin interpellationem (nominative interpellatio) "an interruption," noun of action from past participle stem of interpellare "to interrupt by speaking," from inter "between" (see inter-) + pellare, collateral form of pellere "to drive" (see pulse (n.1)). The parliamentary sense is attested in English from 1837, from French.
interrogative (adj.): "asking or denoting a question," c. 1500, from Late Latin interrogativus "pertaining to a question," from interrogat-, past participle stem of Latin interrogare "to ask, question, inquire; interrogate judicially, cross-examine," from inter- "between" (see inter-) + rogare "to ask, to question" (see rogation). As a noun, "word implying a question," 1520s. Related: Interrogatively.
interrogator (n.): 1751, from French interrogateur (16c.) or directly from Late Latin interrogator, agent noun from Latin interrogare "to ask, question" (see interrogation).
interrogatory (adj.): "containing or expressing a question," 1570s, from Late Latin interrogatorius "consisting of questions," from past participle stem of Latin interrogare "to ask, question, inquire; interrogate judicially, cross-examine," from inter- "between" (see inter-) + rogare "to ask, to question" (see rogation).
intersex (n.): "one having characteristics of both sexes," 1917, from German intersexe (1915); see inter- "between" + sex (n.). Coined by German-born U.S. geneticist Richard Benedict Goldschmidt (1878-1958). Intersexual is from 1866 as "existing between the sexes, pertaining to both sexes;" from 1916 as "having both male and female characteristics." Related: intersexuality.
interruption (n.): late 14c., "a break of continuity," from Latin interruptionem (nominative interruptio) "a breaking off, interruption, interval," noun of action from past participle stem of interrumpere "to break apart, break off" (see interrupt (v.)). Meaning "a breaking in upon some action" is from c. 1400; that of "a pause, a temporary cessation" is early 15c.
intertwine (v.): 1640s (trans.), a hybrid from inter- + twine (v.). Intransitive sense is from 1782. Related: Intertwined; intertwining.
interurban (adj.): 1883, from inter- "between" + Latin urbs "city" (see urban (adj.)).
interventionism (n.): 1852, from intervention + -ism. Interventionist, as a noun, is recorded from 1846, originally in the international sense.
interweave (v.): 1570s (trans.), hybrid from inter- + weave (v.). Intransitive sense from 1827. Related: Interweaving; interweaved; interwove; interwoven.
interwork (v.): c. 1600, a hybrid from inter- "between" + work (v.). Related: interworking. Past tense can be either interworked or interwrought.
intestacy (n.): "condition of dying without leaving a valid will," 1740, from intestate + -acy.
intervent (v.): "to come between" (obsolete), 1590s, from Latin interventus, past participle of intervenire "to come between, interrupt," from inter- "between" (see inter-) + venire "come" (see venue). Related: Intervented; interventing.
interspecific (adj.): "existing between species," 1889, from inter- "between" + specific, used here as an adjective to go with species.
interstitial (adj.): "pertaining to or situated in an interstice," 1640s, from Latin interstitium "interval" (see interstice) + -al (1). Related: Interstitially.
intersubjective (adj.): "existing between conscious minds" [OED], 1883, from German intersubjective (1881); see inter- "between" + subjective (adj.).
intestine (n.): "lower part of the alimentary canal," early 15c., from Middle French intestin (14c.) or directly from Latin intestinum "a gut," in plural (intestina), "intestines, bowels," noun use of neuter of adjective intestinus "inward, internal," from intus "within, on the inside," from PIE *entos, suffixed form of root *en "in" (see in).

Distinction of large and small intestines in Middle English was made under the terms gross and subtle. Intestine also was used as an adjective in English 16c.-19c. with a sense (as in French) of "internal, domestic, civil."
intestinal (adj.): early 15c., from medical Latin intestinalis, from Latin intestinum "an intestine, gut" (see intestine).
intice (v.): obsolete spelling of entice. Related: Inticed; inticing.
intolerance (n.): 1765, "unwillingness to endure a differing opinion or belief," from Latin intolerantia "impatience; unendurableness, insufferableness; insolence," from intolerantem "impatient, intolerant" (see intolerant). There is an isolated use from c. 1500, with an apparent sense of "unwillingness." Especially of religious matters through mid-19c. Now-obsolete intolerancy was used in same sense from 1620s; intoleration from 1610s. Meaning "incapacity to bear or endure" is by 1844.
intolerant (adj.): 1735, "unable or unwilling to endure" (a condition, etc.), from Latin intolerantem (nominative intolerans) "not enduring, impatient, intolerant; intolerable," from in- "not" (see in- (1)) + tolerans, present participle of tolerare "to bear, endure" (see toleration).

Meaning "not disposed to endure contrary opinions or beliefs, impatient of dissent or opposition" is from 1765. Of plants, with reference to deep shade, from 1898. The noun meaning "person or persons who do not favor toleration" is from 1765. Related: Intolerantly.
intonate (v.1): "to intone, recite in a singing voice," 1795, from Medieval Latin intonatus, past participle of intonare "sing according to tone" (see intone). Compare Italian intonare, French entonner. Related: Intonated; intonating.
intonation (n.): 1610s, "opening phrase of a melody," from French intonation (14c.), from Medieval Latin intonationem (nominative intonatio), noun of state from past participle stem of intonare (see intone). From 1788 as "action of intoning." Meaning "modulation of the voice in speaking, utterance of tones" is from 1791.
intra-cellular (adj.): also intracellular, "existing or happening inside a cell," 1842; see intra- "within" + cellular.
intramuscular (adj.): also intra-muscular, 1874, from intra- "within" + muscle (Latin musculus) + -ar.
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- (1) "a foot" (see foot (n.)).
do-it-yourself: as a modifier, attested by 1941. The expression is much older.
drive-in (adj.): in reference to of restaurants, banks, etc., 1929; from drive (v.) + in. Of movie theaters by 1933 (the year the first one opened, in Camden, N.J.).
Ireland: 12c. in Anglo-Norman, a Germanic-Celtic hybrid, with land (n.) + Celtic Eriu (see Irish (n.)).
Irma: fem. proper name; see Emma.
interject (v.): 1570s, back-formation from interjection or else from Latin interiectus, past participle of intericere "to throw between, insert, interject." Related: Interjected; interjecting.
incipience (n.): "beginning, commencement," 1792, from incipient + -ence. Incipiency is from 1764.
intercostal (adj.): "between the ribs," 1590s; see inter- + costal.
infatigable (adj.): "untiring," c. 1500, from French infatigable (15c.) or directly from Late Latin infatigabilis "that cannot be wearied," from in- "not, opposite of" (see in- (1)) + fatigabilis "that may be wearied," from Latin fatigare "to weary" (see fatigue (n.)).
inflorescence (n.): 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.
self-immolation (n.): also self immolation, 1817, from self- + immolation.
self-incrimination (n.): also self incrimination, 1892, from self- + incrimination.
self-indulgent (adj.): also self indulgent, 1791, from self- + indulgent. Related: Self-indulgently.
ilex (n.): "evergreen oak," late 14c., from Latin ilex "holm-oak, great scarlet oak," perhaps from an extinct non-Indo-European language.
ilia: Latin plural of ilium (see ileum).
iliac (adj.): 1510s, "pertaining to colic," from Middle French iliaque (16c.) or directly from Late Latin iliacus, from ileus "severe colic" (see ileus).