In linguistics, a neologism (niːˈɒlədʒɪzəm; also known as a coinage) is any relatively recent or isolated term, word, or phrase that nevertheless has achieved popular or institutional recognition, and is becoming accepted into mainstream language. Most definitively, a word can be considered a neologism once it is published in a dictionary. Neologisms are one facet of lexical innovation, i.e. linguistic phenomena that introduce new terms and meanings into a language's lexicon. The most precise studies into language change and word formation, in fact, identify the process of a "neological continuum": a nonce word is any single-use term that may or may not grow in popularity; a protologism is such a term used exclusively within a small group; a prelogism is such a term that is gaining usage but still not mainstream; and a neologism has become accepted or recognized by linguistic institutions.
Neologisms are often driven by changes in culture and technology. Popular examples of neologisms can be found in science, fiction (notably science fiction), films and television, branding, literature, jargon, cant, linguistics, the visual arts, and popular culture.
Former examples include laser (1960) from Light Amplification by Stimulated Emission of Radiation; robot (1941) from Czech writer Karel Čapek's play R.U.R. (Rossum's Universal Robots); and agitprop (1930; a portmanteau of "agitation" and "propaganda").
Neologisms are often formed by combining existing words (see compound noun and adjective) or by giving words new and unique suffixes or prefixes. Neologisms can also be formed by blending words, for example, "brunch" is a blend of the words "breakfast" and "lunch", or through abbreviation or acronym, by intentionally rhyming with existing words or simply through playing with sounds. A relatively rare form of neologism is when proper names are used as words (e.g., boycott, from Charles Boycott), guy, dick, and Karen.