Complier
A compiler is a type of computer program that translates between a source language and a target language. It's most commonly used to convert source code into machine code or assembly for your computer to execute, although not always. Some compilers are used to produce code for a different CPU architecture or operating system.
Note
These are not the only types of compiler, there are also:
- Decompilers which go from low-level to high-level languages.
- Rewriters that change the expressions without changing the language.
- Interpereters that translate then execute the translated code.
And many more variations which I can't be bothered to mention.