These terms refer to congeries of specialized and non-standard words and expressions used by a subculture or subdivision within a larger group sharing a common language, especially when such expressions would be thought illiterate, odd or unintelligible by the average user of the language. Slang refers to the extremely informal language used by the members of an in-group in place of more usual expressions; slang may include abbreviated or made-up words, novel expressions, grammatical distortions and other violations or departures from accepted usage. Sometimes the expressions of an in-group that gain popularity or a wider understanding are still considered slang by some people so long as they remain distinct from standard or even formal usage.

Argot refers to the slang of a very limited group which feels threatened by the hostility of society as a whole; this word was once restricted to the slang of criminals or thieves, but it can now apply to any use of language by minority groups that is marked by protective euphemisms and codelike secretiveness: the popular adoption of the word "camp" from homosexual argot ; comparing the argots of the circus worker and the jazz musician; "Mr. Charlie" and "ofay" are terms for the white man in the argot of the U.S. Negro ghetto. Cant once was exactly synonymous with argot in referring to the private language of thieves, but now it generally refers especially to the inflated, ingrown or pompous language of a respected profession, especially in one of the social sciences: a learned paper full of sociological cant .

In a technical sense, jargon refers to a simple cross-breeding of two languages to facilitate communication, such as pidgin English. More generally, the word would be understood as referring to the extremely technical terms in use among specialists in any abstruse field: words like "tweeter" and "woofer" and other bits of jargon bandied about by hi-fi enthusiasts.