A high-level programming language known for its abundant use of parentheses. Macintosh Common Lisp is an implementation of Lisp that provided a development environment with tight integration with the Mac OS toolbox. An early, unreleased version of Newton OS known as Bauhaus was developed using the Lisp-like language Ralph.
Wikipedia: Macintosh Common Lisp
Talking with Mikel Evins about the Lisp-based Newton OS