What does “Idempotent” mean in software?

I had never heard the word “idempotent” when I started at my first software job. I had a liberal arts education and had been working in nonprofit and school management before my career change. I suspect I’m not alone in this total lack of awareness of the concept! So let’s talk about it.

What does it mean?

It means you can do the same thing with the same inputs any number of times, and it won’t change the end result.