Lisp is a language family. Popular, well known choices include for example: Common Lisp, Scheme, Racket, Emacs Lisp and Clojure. There are countless production

Lisp is a language family. Popular, well known choices include for example: Common Lisp, Scheme, Racket, Emacs Lisp and Clojure. There are countless production systems written in these languages, ranging from embedded, to web apps to infrastructure tooling. The specific domains where they're applied, are just as diverse as one could imagine. The more interesting question is "Why would someone use any of these languages?". Niche languages are typically associated with risk in the business world. But the thing is that Lisp just keeps surviving, evolving and finding new problems and domains to tackle. My personal opinion is that these languages represent the powerful combination of freedom, stability and engagement. A Lisp is inherently non-condescending as it gives you more powerful tools than most other languages, but it's also very reliable because it's built on a very well understood, minimal foundation. Last but not least you are programming in a way that is very engaging. You are right there in the running program.