Colloquialism (also called colloquial language, everyday language, or general parlance) is the linguistic style used for casual (informal) communication. It is the most common functional style of speech, the language normally employed in casual conversation and other informal contexts. Colloquialism is characterized by the frequent use of expressive phrases, idioms, anthropocentrism, and a lack of specialized focus, and has a rapidly changing lexicon. It can also be distinguished by its usage of formulations with incomplete logical and syntactic ordering.
A specific instance of such language is termed a colloquialism. The most common term used in dictionaries to label such an expression is colloquial.