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Etymology and origin of the English word in-

English has three prefixes spelled in-: the native one from in, one from Latin with the same meaning, and one from Latin that negates.[1][2][3] The first two came to be felt as one, and it is often impossible to tell which an English word has.[1] A fourth, intensive, in- of Old and Middle English (inred, inwise) is obsolete.[1][4]

Pronunciation

in-1 native, inward

Confidence
Established
Formation
Inherited
Inherited from
Old English in- via Middle English
Ultimate origin
Proto-Indo-European *h₁én

Etymology

The native prefix is inherited from Middle English in-,[4][2] inherited from Old English in-,[1][2] partly inherited and partly formed directly from the adverb and preposition in.[1][6][2] It goes back to the same Germanic base as the preposition, Proto-Germanic *in,[1][7][8] which is from Proto-Indo-European *h₁én.[8] It is cognate with Old Frisian in-, Dutch in-, Old Saxon in-, Old High German in-, German ein-, Old Norse í- and Gothic 𐌹𐌽- (in-).[1]

Earliest recorded meaning

In Old English it was stressed and went on nouns and adjectives for something within, as in inland, and on nouns of action for a movement inwards, as in ingang (“entrance”) and infær (“entry”).[1] It also went on participles, as in inboren (“native”).[1]

Semantic evolution

New formations of the same kind continued in Middle and later English, among them inwit and incomer.[1] Old English verbs with on- and similar forms died out in time.[9] Later uses often oppose it to out-, for what lies within, or for the side in possession in a game.[1] Barnhart separates a recent type, in-house and in-country, which grew from prepositional phrases.[2]

Timeline

  • Old English – in- living inside, in Ælfric's Glossary, and -ing nouns of movement in the Lindisfarne Gospels.[1]
  • before 1400 – with present participles of inward movement.[1]
  • 1828 – of the side in possession: in-player.[1]

Meanings

Prefix

  1. Added to verbs and their derivatives to mean in, within or inward: inborn, income, inlet.[6][10][11]
  2. Added to nouns to mean internal or living inside: inland, inpatient.[1][6]
  3. Added to nouns to mean within a group or organization: in-house.[2]

Word family

in-2 Latin, into

Confidence
Established
Formation
Borrowing
Borrowed from
Old French in- via Middle English
Ultimate origin
Proto-Indo-European *h₁én

Etymology

The Latin prefix meaning in or into is inherited from Middle English in-,[4][10] borrowed from Old French in-, also en-, and directly borrowed from Latin in-,[1][3][9][10] from the adverb and preposition in,[1][2] from Proto-Indo-European *h₁én.[8][9] It is thus cognate with the native prefix.[1][8] The forms il-, im- and ir- of later Latin, before l, labials and r, arose by assimilation, and the prefix was lost before gn.[1][9][3]

Earliest recorded meaning

In Latin it went mainly on verbs and their derivatives, meaning into, in, on, towards or against, and sometimes it added only intensity or nothing obvious.[1][3][6]

Semantic evolution

Inherited Old French words changed it to en-, while learned ones kept in-.[1][3] From the 14th century English increasingly respelled en- as in- where the Latin source was clear, as in increase and inherit.[1] Many words had both forms in the 15th and 16th centuries.[1] Some still do, sometimes with a difference of sense, as with ensure and insure.[1][9] It can also make a verb transitive with little change of meaning.[2]

Timeline

  • 14th century on – in-, im- increasingly replaces en-, em- in English.[1]
  • 15th and 16th centuries – many words occur with both prefixes.[1]

Meanings

Prefix

  1. Forming verbs that mean in, into, within or towards: infiltrate, immigrate.[12][10][2]
  2. Used with intensive or causative force: inflame, imperil.[12][6][2]

Word family

in-3 not

Confidence
Established
Formation
Borrowing
Borrowed from
Old French in- via Middle English
Ultimate origin
Proto-Indo-European *n̥-

Etymology

The negative prefix is inherited from Middle English in-,[4][10] borrowed from Old French in- and directly borrowed from Latin in-,[1][10][3] from the same Indo-European base as un-1 and Ancient Greek ἀν- (an-), Proto-Indo-European *n̥-, from *ne (“not”).[1][9][3][2] It is related to Latin nōn and thus to non-.[12] It has the same assimilated forms as the other Latin prefix, il-, im- and ir-, and a few Old French words changed it to en-, as in enemy and envy.[1][3][9]

Earliest recorded meaning

In Latin it went on adjectives and their derivatives, and rarely on other words, to express negation or lack: infēlīx (“unhappy”), inūtilis (“useless”), innocēns (“not hurtful”).[1][3]

Semantic evolution

English has it from at least the 13th century in borrowings from Latin and French, such as incest and innocent.[1] Its own formations, such as indepartable, appear by the 14th century.[1] It goes mostly on words of Latin or Romance origin, and exceptions such as inspeakable are often remodellings of older words in un-.[1] Since the Latin prefixes were identical in form, confusion goes back to Rome, where impressus could mean pressed or unpressed, and it survives in inflammable, which does not mean not flammable.[9]

Timeline

  • 13th century – in words borrowed from Latin and French: inobedience, incest, innocent.[1]
  • 14th century – first formations in English: indepartable, ineschewable, indisposed.[1]
  • 16th century – on some native bases: inspeakable, intellable.[1]

Meanings

Prefix

  1. Added to adjectives and their derivatives to mean not: incredible, illegal, irregular.[12][10][2]
  2. Added to nouns to mean the opposite or absence of something: inattention, inequality.[2][11]

Word family

References

  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z 27 28 29 30 31 32 33 34 35 36 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  2. ^ a b c d e f g h i j k l m Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
  3. ^ a b c d e f g h i Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
  4. ^ a b c d Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
  5. ^ Jones, Daniel (2011), Cambridge English Pronouncing Dictionary, 18th ed., ed. Peter Roach, Jane Setter and John Esling, Cambridge: Cambridge University Press
  6. ^ a b c d e Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
  7. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
  8. ^ a b c d Kroonen, Guus (2013), Etymological Dictionary of Proto-Germanic, Leiden Indo-European Etymological Dictionary Series 11, Leiden / Boston: Brill
  9. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  10. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  11. ^ a b Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press
  12. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins

Related etymologies

  • wet · also from Old English
  • weapon · also from Old English
  • sing · also from Old English
  • sight · also from Old English
  • hide · also from Old English
  • dumb · also from Old English
  • shame · also from Old English
  • roof · also from Old English
Cite this entry

“In-.” Etymologically, 6 Nov. 2026, etymologically.com/en/in-. Accessed 6 Nov. 2026.

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