Ronald H. Petersen

(Based, in part, on Paclt, J. 1952. Taxon 1: 110-111.)


ANTONYM: Names which are not synonyms; free-standing, independent names.

AUTONYM: A name automatically created at all lower subordinate ranks when a name is introduced for a taxon at a principle rank. See Arts 19, 22, 26.

BASIONYM: [often misspelled as "basinym"] A name at its introduction; changes in rank and/or position create new combinations of names, but do not alter the basionym. See Art. 33, para. 2

EPONYM: That for which a taxon is named. e.g. Astragalus alpinus f. lepagei Rouss. See Taxon 32(1): 92-93.

GENONYM: [often misspelled "geneonym"]. A genus name.

HOMONYM: Identically constructed names based on different types; identically spelled names for different taxa. (Eichler, Taxon 12: 15. 1963).

[Donk has referred to "monodelphus homonyms," but I do not know the meaning of this term]

HYPONYM: A name not assignable to a definable taxon (by lack of adequate circumscription or type; a genus without species, etc.).

IDIONYM: A homonym(s) created by misinterpretation or misidentification of specimens of different taxa.

ISONYM: Two basionyms based on the same type. [Nicolson has used "pseudo- isonyms" as basionyms based on the same type at one rank, but not at another]

LOGONYM: A name later declared a type or "genotype."

METONYM: [also spelled "metaeonym"] A later (superfluous) name introduced based on the type of an extant basionym.

Genus rank or higher: A name based on a type belonging to the same group as the type of an earlier name.

MORPHONYM: (zoological) A species name.

NEONYM: A wholly substituted name (nomen novum).

PARANYM: [Eichler. Taxon 12: 15. 1963] Orthographically variant names (candidates for homonymy or not) based on different types.

POLYONYM: A name used in widely varying and confusing senses (see Art. 69).

SYNAGONYM: Names based on different types sometimes considered contaxic.

SYNOECONYM: Two or more names based on different types within the same taxon (taxonomic synonym).


1) Taxonomic ("facultative") synonym: names for contaxic taxa, based on different types.

2) Nomenclatural ("obligate") synonym: two or more names based on one type.

TAUTONYM: A combination in which the epithet wholly repeats the first name (Ex: Cantharellus cantharellus; see Art. 23).


1) Names based on one type (cf. isonym; metonym).

2) Zoological: a trivial name indicating some typical state.

mushroom2.jpg (3909 bytes)