HAPAX LEGOMENON

A 'hapax legomenon' (pl. ''hapax legomena'', though sometimes called ''hapaxes'' for short) is a word which occurs only once in the written record of a language, in the works of an author, or in a single text. If a word is used twice it is a ''dis legomenon'', thrice, a ''tris legomenon''. Beyond ''tetrakis legomenon'' (four times), a word is not rare enough to note.
''Hapax legomenon'' is from the Greek ἅπαξ λεγόμενον "[something] said only once."
Some examples of ''hapax legomena'' in a given language or body of work are:

★ ''Honorificabilitudinitatibus'' is a ''hapax legomenon'' of Shakespeare's works.

★ ''Nortelrye'', a word for "education", occurs exactly once in Chaucer.

★ ''slæpwerigne'' occurs exactly once in the Old English corpus, in the Exeter Book. There is debate over whether it means "weary with sleep" or "weary for sleep."

★ ''Autoguos'' (αυτογυος), an ancient Greek word for a sort of plough, is found once (and exclusively) in Hesiod, the precise meaning remaining obscure.

★ ''Panaorios'' (παναωριος), ancient Greek for "very untimely", is one of many ''hapax legomena'' of the ''Iliad''.

★ ''Flother'', a synonym for snowflake, is a ''hapax legomenon'' of written English pre-1900, found in a manuscript from around 1275.

★ ''Gvina'' (גבינה-cheese) is a ''hapax legomenon'' of Biblical Hebrew, found in Job 10:10. The word has been extremely common in Hebrew since its appearance in the Bible. There are more examples, like the word Hashmal (חשמל - electricity or lightning) that appears only in Ezekiel 1:4. Today it is the only word used to refer to electricity (never lightning).

★ ''Gopher wood'' is mentioned once in the Bible, in the instruction to make Noah's ark "of gopher wood". Because of the single appearance, the literal meaning is lost. ''Gopher'' is simply a transliteration, although scholars today tentatively suggest that the wood intended is cypress.

★ ''Wimble'', a word appearing in James Joyce's ''Ulysses'' (''U'' 7.1071). Joyce told Stuart Gilbert that it was a ''hapax legomenon''. The ''Oxford English Dictionary'' lists a Yorkshire-Lancashire dialect usage of ''wimble'' as "active, nimble", but the sense that Joyce seems to intend is "giddy, confused".
The term ''hapax legomenon'' is popular among Bible scholars, who take the number of ''hapaxes'' in a putative author's corpus as an indication of his vocabulary and thereby argue for or against attribution. The identification of a word as a ''hapax'' by these authors means that it occurs once in the Bible or, more specifically, once in the New Testament.
Note that the term refers to a word's appearance in a body of text, not to its origins, nor to its prevalence in speech. It thus differs from a nonce word, which may never be recorded, or may find currency and be recorded widely, or may appear several times in the work which coins it, and so on.