GLOSSARY OF -ONYMS AS APPLIED TO BOTANICAL NOMENCLATURE
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.