Infix and circumfix are less so, as they are not important in European languages.
From the en.wikipedia.org
Or is usually expressed with the prefix operator A, or with an infix operator.
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And is usually expressed with the prefix operator K, or an infix operator.
From the en.wikipedia.org
You cannot split them and, at best, can only create an infix, which would be non-sensical.
From the economist.com
In mathematics, France uses the infix notation like most countries.
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The subject prefix is placed first, and then the object infix.
From the en.wikipedia.org
An infix is a grammatical unit like a prefix or suffix except it comes in the middle of a word.
From the en.wikipedia.org
A small glyph placed inside another is called an infix.
From the en.wikipedia.org
The infix is normally seen in the present tense stem, and is not present in the third and fourth principal parts.
From the en.wikipedia.org
More examples
An affix that is inserted inside the word
Insert: put or introduce into something; "insert a picture into the text"
Attach a morpheme into a stem word
An infix is an affix inserted inside a stem (an existing word). It contrasts with adfix, a rare term for an affix attached to the outside of a stem, such as a prefix or suffix.
A morpheme inserted inside an existing word, such as -i- and -o- in English; To instill; To insert a morpheme inside an existing word
An operator that comes in between its operands, such as multiplication in 24 * 7.
While a prefix is a meaningful syllable or collection of syllables inserted before a main word, and a suffix is a meaningful syllable or collection of syllables added to the end of a main word, an infix is a meaningful syllable splitting in half a larger word. ...
A string (see there) that may occurs in any position within a word (see there). If an infix occurs in the beginning of a string, it's called prefix (see there), if it occurs at the end of a string, it's called suffix (see there). ...
A strong definition of an infix might be a morpheme which is added inside a root morpheme in the formation of a word. In a language like English, infixes, so defined, do not occur, since the root morpheme is indivisible. ...