-onym

Morphemes with the affix -onym (from the Greek for name) are designations for either a closed set of grammatical morphemes that refer to relationships between word pairs, such as synonym and antonym; or they may stand for classical compound nouns of an open type that refer to a particular subject, such as toponym, charactonym, etc. By analogy they may be freely created, sometimes for no other reason than to give an erudite impression of the user who expects his listeners to understand Greek, and it is in this way that words such as ornithonym or ichthyonym may be formed.

The usage of the word pairs is of great importance in grammar. Some morphemes ending in -onym may represent words that contain components, in the way house may contain window, roof, and door, or they may be words so contained in others, such as steering-wheel and engine in car. They may be generic words that stand for a class or group of equally-ranked items, such as tree for beech or elm, or belong within that class, such as lily or violet in flower. They may have the same or a similar meaning as a differently spelled word, such as sofa or couch, or they may stand in direct contrast to another, such as useful and useless.

Some morphemes have the -nym form rather than the -onym form, such as ananym or hypernym, but that may be more for ease of pronunciation than for etymological reasons.

Most -onyms may have suffixes added to them and in this way form derivatives with the endings -onymy, -onymous, -onymic, etc., in new constructions. Others may reverse this process by removing suffixes in back-formations, especially if the new morphemes thus formed sound plausible enough to have been the root form in first place.

A list of -onym words

• acronym - an abbreviation formed from the initials of one or more words that is pronouncable like a normal word, such as NATO
• allonym - an author's name of another person's, often a well-known person's name
• anacronym - portmanteau morpheme of anachronism + acronym that may be an acronym, abbreviation, or initialism but that is so well established that its origin is no longer remembered. As this seems a specious reason (after all any acronym may be looked up in a dictionary) it may be more applicable to abbreviations, etc., that are at risk of becoming out-of-date and being superseded by newer abbreviations, such as AD being replaced by CE (Common Era)
• ananym - a name written backward and used as pseudonym
• anonym - word defining anything created anonymously, or the person who has created it; an unknown author; a pseudonym
• anthroponym - a classical compound word denoting a human name
• antonym - one of the words of the word pair antonym and synonym that indicates the exact opposite meaning of another word, an antithesis, such as high and low
• aptronym - name appropriate to its owner's occupation or physical properties as in Goldsmith or Longman
• aristonym - one of the classical compound nouns of -onym words that denotes a name that is derived from a high rank or a title of nobility
• backronym - portmanteau morpheme of back + acronym that appears to fit an existing word but has really been created as an acronym, such as BASIC (Beginner's All-purpose Symbolic Instruction Code)
• caconym - one of the words of the word pair caconym and euonym; a word that is wrongly applied; a misnomer; the incorrect name for something, especially in the classification of plants, etc.
• capitonym - a compound word of capital + -onym of a word that changes its pronunciation and meaning when it is capitalized, and usually applies to capitalization due to proper names or eponyms, as in August - august, or Polish - polish
• charactonym - a compound word, the name of a fictional character that may be reflected in his personality traits, as in Shakespeare's Pistol or Bottom; or Titus Feuerfuchs in Johann Nestroy's Der Talisman, who attempts to hide his fiery-red hair with a black wig
• contronym - a word that may have opposite meanings in different contexts, such as to cleave - to stick to, adhere, and to cleave - to split
• cryptonym - a classical compound noun denoting a code name; a word or name used clandestinely to refer to another name or word
• demonym - one of the classical compound nouns, a name of persons/people that refers to the place they come from, such as the Assyrian, or the Briton
• eponym - a botanical, zoological or place name that derives from a real or legendary person; a name for a real of hypothetical person from whom a botanical, geographical or zoological name is derived; a person after whom a medical condition is named, or the condition so named
• ethnonym - a classical compound word denoting a name of an ethnic group
• euonym - one of the words of the word pair euonym - caconym; a word well suited to a person, place or thing so named; a pleasant name
• exonym - a name used by one group of people for another group, but who call themselves by a different name, such as the name Germans used by English-speakers for Deutsche, the name German-speakers use
• heteronym - one of the words of the word pair homonym and heteronym; a word that is spelled in the same way as another but that has a different sound and meaning, such as bow of the ship and bow and arrow.
• holonym - one of the words of the word pair holonym and meronym; a word for the whole and of which other words are part, in the way house contains roof, door and window; or car comprises steering-wheel and engine
• homonym - one of the words of the word pair homonym and heteronym, or the word pair homonym and isonym; word that is pronounced and spelt the same way as another, but has a different meaning, such as bat, the mammal, and bat, the club
• hydronym - a classical compound word denoting a name of a body of water
• hypernym/hyperonym - one of the words of the word pair hypernym and hyponym; a generic type of word that stands for a class or group of equally-ranked items, such as tree for beech or elm, or house for chalet or bungalow. A hypernym is superordinate to a hyponym.
• hyponym - one of the words of the word pair hyponym and hypernym; an item that belongs to and is equally-ranked in a generic class or group, such as lily or violet in the class of flowers; or limousine or hatchback in the class of automobiles. A hyponym is subordinate to a hypernym
• isonym - often one of the words in the word pair homonym and isonym; word that is spelt the same as another word but sounds differently; or is of the same derivation as another and is therefore a cognate of that word
• meronym - one of the words of the word pair meronym and holonym; a word that names a part that belongs to and is therefore subordinate to a larger entity; a part - whole relationship, such as door or window in house, or engine or steering-wheel in car
• metonym - a word that substitutes a part for the whole it is associated with, such as crown for monarch. It is associated with its derivative, the figure of speech, metonymy
• paronym - a word that is related to another word and derives from the same root; a cognate word, as in dubious and doubtful
• patronym or patronymic - a classical compound word denoting a name adopted from the father's or ancestor's name, such as Johnson - John's Son; MacDonald - Son of Donald; O'Brien - Son of Brien; Ivanov - Son of Ivan, etc.
• pseudonym - a false and fictitious name adopted by an author; a pen name
• retronym - a replacement of an original simple noun by a modified noun, by having one or more components added to it, as in watch that existed on its own originally and then had a preceding analog added to it, in order to differentiate it from a digital watch
• synonym - one of the words of the word pair synonym and antonym; a word equivalent in meaning or nearly so to another word; a word that may be substituted for another word that has the same or a similar meaning, such as near and close
• tautonym - a binomial or scientific name in the taxonomy of animals in which the generic and specific names are the same as in Gorilla gorilla; a scientific name in which the specific name is repeated, as in Homo sapiens sapiens as distinct from Homo sapiens neanderthalensis; a noun component that is repeated, such as aye-aye or tom-tom; a personal name where both forename and surname are identical as in Francis Francis
• toponym - a classical compound noun that stands for a place or geographical name; the name of an area of the body, as distinguished from the name of an organ
• troponym - a verb that indicates more precisely the manner of doing something by its replacing a verb of a more generalized meaning, thus the verb to stroll indicates a more leisurely, casual manner of to walk.