Concept: grammatical marker

Definition

A (grammatical) marker is a °clitic or an °affix.

Comments

Linguists almost never discuss the meaning of "(grammatical) marker", but the term is very widely used, especially in the description of non-European languages, where it is taken as a cover term for an affix and a function word (= clitic). Matthews's (2007) definition (as the "realization of a unit") is too vague, and also too broad because one would say, for example, that plural can be "realized" as vowel change, but vowel change would not be considered as a marker.

Wikipedia

marker

SIL Glossary

marker

Quotation

"marker: Any unit or feature conceived (a) as the realization of a unit etc. at a more abstract level of representation, or (b) as indicating something to a potential addressee. Thus a ‘case marker’ or ‘tense marker’ is an inflection etc. which realizes a case or a tense; a boundary marker indicates a boundary e.g. between words; the in the house ‘marks’ the phrase as definite. A social marker likewise gives an indication of the status of a speaker in society." (Matthews 2007)

Sources

Matthews 2007