PicoLisp is a programming language, a dialect of the language Lisp. It runs on operating systems including Linux and others that are Portable Operating System Interface (POSIX) compliant. Its most prominent features are simplicity and minimalism. It is built on one internal data type: a cell. On the language level, a programmer can use three different data types (numbers, symbols, and lists) being represented by cells and differentiated by bits at the end of the cell. It is free and open-source software released under an MIT License (X11).