Chresonym

In biodiversity informatics, a chresonym is the cited use of an already-existing taxon name, usually a species name, within a publication. The term is derived from the Greek χρῆσις chresis meaning "a use" and refers to published usage of an existing name.

The technical meaning of the related term synonym is for different names that refer to the same object or concept. As noted by Hobart and Rozella B. Smith, zoological systematists had been using "the term (synonymy) in another sense as well, namely in reference to all occurrences of any name or set of names (usually synonyms) in the literature." Such a "synonymy" could include multiple listings, one for each place the author found a name used, rather than a summarized list of different synonyms. The term "chresonym" was created to replace this second sense of the term "synonym." The concept of synonymy is furthermore different in the zoological and botanical codes of nomenclature; under the ICZN, a synonym is an available name (i.e., it has its own description, authorship, date, and type specimens), while a chresonym is not.

A name that correctly refers to a taxon is further termed an orthochresonym while one that is applied incorrectly for a given taxon may be termed a heterochresonym.