package manager
Like a supply clerk who fetches and tracks parts, it installs the code libraries your project depends on and keeps versions organized.
Think of someone who orders parts, logs where they came from, and makes sure they fit together. A package manager installs libraries, which are bundles of code someone else wrote, and tracks their versions so your app builds the same every time.
This matters because modern apps stand on many small pieces. Without a manager, installing and updating them is slow and error prone.
In practice you run a command to add a library, it records the choice in a list file, and it writes a lockfile, which is a precise snapshot so teammates and servers install the exact same versions.