Concept: indefinite article

Definition

[[An indefinite article is a bound morph that frequently occurs in indefinite nominals and that never occurs in definite nominals.]]

Croft's comparative concept
indefinite pronoun/article (CXN):

indefinite pronoun/article (CXN) = this term is applied to referring phrases – pronouns and articles combined with nouns – that are associated with the bottom end of the information status continuum, where the identity of the referent is not known to speaker or hearer (or both). This includes pragmatically specific, pragmatically nonspecific (but semantically specific), and various categories of nonspecific refer- ents (see Table 3.4 and Sections 3.4–3.5). Example: a glass bowl is an example of an indefinite referring phrase, used in a context where the individual glass bowl in ques- tion is not identifiable by the hearer. (Table 3.4, Section 3.3.1)

Wikipedia
(no direct counterpart)
SIL Glossary
indefinite