Hapax legomenon

Word that only appears once in a given text or record

In corpus linguistics, a hapax legomenon is a word or an expression 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 but more than once in that particular work. Hapax legomenon is a transliteration of Greek ἅπαξ λεγόμενον, meaning "said once".

This keyword could refer to multiple things. Here are some suggestions: