A neologism is a word, phrase, or expression that has recently entered a language and is gaining popularity of use.
Recent examples of this are internet related terms such as blog, meme, and selfie that have been recently coined and are now in frequent use. Neologisms are particularly common in young children who frequently assign idiosyncratic names to various objects such as naming their favorite blanket. In psychiatry, it is not uncommon for severely impaired clients (patients with thought disorders, autism or severe psychopathy such as schizophrenia) to use neologisms; words or usages, or nonsensical phonemic groups, in ways that are unique to the user. The latter of these is sometimes referred to as word salad.