You are right. We forgot to explain it. npm stands for Node Package Manager. It's a library and registry for JavaScript software packages. A lot of of open-source developers use npm to share software.
Discussion
Also other programming languages like Java, PHP, Python et cetera have their package managers:
- ant, maven (Java)
- composer (PHP)
- pip (Python)
And also cmake in some way. Except ant, all above does download packages for you.