affixus

Affixus is a term used in morphology to denote a hypothetical mechanism of word formation in which bound morphemes attach to a stem at an internal position, as opposed to conventional prefixes or suffixes that attach at word boundaries. The word derives from Latin affixus meaning "attached."

In theory, affixus encompasses infixes and other internal affixes that alter the internal structure of a base root rather than adding a new outer layer. The concept is mainly encountered in typological discussion and in analyses of languages with rich infixation systems.

Proponents view affixus as a useful category to describe morphological processes that cannot be captured by simple prefixation or suffixation schemes. Critics argue that distinguishing internal attachment from both infixation and circumfixation can be methodologically murky and that the term is not universally adopted in descriptive grammars.

In practice, examples of internal affixation can be observed in languages with infixes that insert within a root or stem, producing a change in meaning or part of speech without adding a separate affix at the left or right edge. Documentation is limited, and the term is most often encountered in theoretical papers exploring the boundaries of affixation typology.

See also affix, infix, circumfix, concatenation.