Quick Answer: In computing, a compiler is software that translates computer code written in one programming language into another language. The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language to create an executable program. There are many different types of compilers which produce output in different useful forms. A cross-compiler produces code for a different central processing unit or operating system than the one on which the cross-compiler itself runs. A bootstrap compiler is often a temporary compiler, used for compiling a more permanent or better optimized compiler for a language.