infix

Etymology

Back-formation from Middle English infixed (“stuck in”), from Latin infixus, past participle of infigere (“to fasten in”).

verb

1. (transitive, archaic) To set; to fasten or fix by piercing or thrusting in.
   to infix a sting, spear, or dart
   Book 1, in Fables, Ancient and Modern, London: Jacob Tonson, p. 11, The fatal Dart a ready Passage found, And deep within his Heart infix’d the Wound:
   Consider that innumerable race of insects, which either are bred on the body of each animal, or flying about infix their stings in him. 1779, David Hume, Dialogues Concerning Natural Religion, part 10, page 100
2. (transitive) To instill.
3. (transitive, linguistics) To insert a morpheme inside an existing word.

noun

1. (linguistics) An affix inserted inside a root, such as -ma- in English edumacation.
2. (some authors when describing agglutinative languages, otherwise dated) A prefix that is not at the beginning of a word, such as the con- of reconcile, or a suffix that is not at the end of a word, such as the -al of nationality.
   The infix position contains (pronominal) object markers, showing agreement with the object(s), which might be one or more noun phrases following the verb, or a foregoing or previously mentioned object marking. 2008, Derek Nurse, Tense and Aspect in Bantu
   […] but the second example contravenes all the rules, as the negative infix should NEVER precede any Set 2 affix present in the complex. 2008, George Hewitt, Are Verbs Always What They Seem to Be?
   […] at least in languages, like Swahili, which exhibit morphologically different tense/aspect infixes in affirmative and negative clauses[…] 2018, Gloria Cocchi, chapter 5, in Structuring Variation in Romance Linguistics and Beyond, →DOI
   The morpheme in question is the reflexive prefix ('infix' in the traditional Bantu terminology). 2023, Bostoen, de Schryver, Guérois & Pacchiarotti, editor, On reconstructing Proto-Bantu grammar, page 709
3. (Bantu linguistics, dated) A prefix that always occurs in the position immediately before the verb root, and which may in turn be preceded by other prefixes.
4. (linguistics, proscribed) A morpheme that always appears between other morphemes in a word, such as -i- and -o- in English (i.e. an interfix).