Puppet
In plain terms
A configuration-management tool enforcing declarative system state.
Going deeper
Puppet defines the desired state of systems in its own language and continuously enforces it via agents. It keeps fleets consistent over time.
Under the hood
Declarative model-based; agents pull and reconcile to desired state, popular in large enterprises.
Examples
Enterprise config management, compliance enforcement, server fleets.
Think of it like...
Like a supervisor who keeps checking and correcting machines back to the approved setup.