Definition of Esoteric programming language

An esoteric programming language (sometimes shortened to esolang) is a programming language designed as a test of the boundaries of computer programming language design, as a proof of concept, or as a joke. There is usually no intention of the language being adopted for real-world programming. Such languages are often popular among hackers and hobbyists. This use of esoteric is meant to distinguish these languages from more popular programming languages. Some more popular languages may appear (in the usual sense of the word) to some, and though these could arguably be called "esoteric programming languages" too, this is not what is meant.