With a compiled language, the human friendly code that gets written is compiled in advance before the code can be run, which may take some significant amount of time depending on complexity, into generally faster and more efficient "machine code" which is what computers actually understand.

Interpreted languages don't get compiled, their code gets translated on the fly between the human friendly code and and what the machine can understand. The advantage of interpreted languages is that they're generally easier and you can test and work out bugs more quickly without spending time compiling.

As a trade off, the interpreted languages can take significantly longer to run the same functions. Which isn't a problem on the small scale, but and add up a lot with more complexity.