A computer program is a set of instructions written in a programming language for the computer and user to understand.
Compiled vs Interpreted
Since code is written in a programming language, the computer must convert them into machine code for the processor.
Compiling code takes the source code and converts into into machine code, creating an executable program file. The executable is much faster, but the file will be larger and not portable.
Interpreting code loads the interpreter into memory which creates the source code for each language as it is running. Interpreting is great for smaller file sizes and portability, but the interpreter needs to be on the computer and is slightly slower.