Here is a question from the past exam.

Which of the following words contains an infix?

a. pedicure

b. intangible

c. temptation

d. biology

e. all of the above

An infix is an affix that is inserted into the middle of a base. But I have no idea how to determine whether a word contains an infix.

  • 2
    Unless you count combining vowels (the -o- in biology or the -i- in pedicure) as infixes (they’re not), I don’t see any infixes in any of those words. The p in temptation is excrescent, but it’s not an affix. Intangible does have an element ‘inserted’ in the middle, but that’s the root (tang-); the rest is a prefix and a suffix, but no infix. Jun 23, 2020 at 18:40
  • In our lecture slides, -o- is called an interfix. Jun 23, 2020 at 18:43
  • Exactly – an interfix (which is non-morphemic) rather than an infix (which is morphemic). Jun 23, 2020 at 18:45
  • 4
    The -n- in intangible was an infix in Latin, (the root is _ *teh₂g-_) but somehow I doubt that's what they mean
    – Colin Fine
    Jun 23, 2020 at 18:47
  • 6
    A poorly worded exam question. As is, these are (present-day) English words and none of them has an infix. If your instructor wanted you to examine their etymology, then the question should include "historically" or "etymologically" (contained), and then in that case Colin Fine would be correct, but that infix would be in Latin, not in English.
    – Alex B.
    Jun 23, 2020 at 19:33

1 Answer 1


An infix is anything that is inserted by morphology after the first segment of a morpheme and before the last segment of that morpheme. If you have a morpheme /pot/ and some morphological process stick [l] inside that, e.g. [plot], that is an infix. If you put it before a root, it is a prefix. If you put it after a root, it is a suffix. If you put it before a root then move it to be before the first vowel, i.e. /l+pot/ → [plot], that is a prefix with metathesis.

In order to know if something is an infix, you have to be able to separate a word into constituent morphemes. Sometimes that is trivial and uncontroversial (un+controversial), and sometimes it is controversial (con+tro-vers-i-al?). It is controversial whether the Latin word controversia is divided into contra+versia or contra+ver-ti-a. The problem is that people (including instructors) often conflate "etymologically connected" with "synchronically in an affixation relation". Thgus, join, juncture is a historical example of the concept "infix" (-n- is infixed in Latin in some forms of the root PIE *yug), but there is no process of infixing in modern English that inserts n.

The fact that "none of the above" is not an option tells you that you have to look at this example diachronically, not synchronically, meaning you need to know the Indo-European source of the words.

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