In
corpus linguistics, a
hapax legomenon ( also or ; pl.
hapax legomena; sometimes abbreviated to
hapax, pl.
hapaxes) is a
word that occurs only once within a context, either in the written record of an entire language, in the works of an author, or in a single text. The term is sometimes incorrectly used to describe a word that occurs in just one of an author's works, even though it occurs more than once in that work.
Hapax legomenon is a
transliteration of
Greek ἅπαξ λεγόμενον, meaning "(something) said (only) once".