# Nixpkgs

_Nixpkgs_ (pronounced "Nix packages") is a big collection of [Nix] expressions, packages (who'd have thought...), and build utilities for the Nix ecosystem.
It is sometimes also called a "Nix standard library" (or Nix stdlib).

Nixpkgs is a mono repo, containing over 80,000 package definitions and the utilities to maintain this set of packages.
It also contains [NixOS](/concepts/nixos) modules and anything required to build and deploy a full Nix system.
Many tools in the Nix ecosystem depend on this standard library to function.

[nix]: https://nixos.org