A neologism is a newly coined word or expression. It may be invented to name a new object or concept, or it may be a playful or experimental formation.

Scientific and technical fields generate neologisms continually as knowledge expands. Literary writers invent words for stylistic effect—Shakespeare’s coinages, Joyce’s portmanteaus, the slang of dystopian fiction. Some neologisms catch on and enter the standard lexicon; most remain temporary or specialized. The internet and social media have accelerated the creation and spread of new terms.

Neologisms can clarify, amuse, or obscure. A well-formed neologism feels inevitable once encountered; a clumsy one feels forced. Dictionaries eventually record those that achieve wide currency. In the meantime, neologisms mark the growing edges of a language—the places where experience has outrun existing vocabulary.

A word that did not exist until someone needed it is a neologism.