Control Node: the machine where Ansible is installed, responsible for running the provisioning on the servers you are managing.
Inventory: an INI file that contains information about the servers you are managing.
Playbook: a YAML file containing a series of procedures that should be automated.
Task: a block that defines a single procedure to be executed, e.g.: install a package.
Module: a module typically abstracts a system task, like dealing with packages or creating and changing files. Ansible has a multitude of built-in modules, but you can also create custom ones.
Role: a set of related playbooks, templates and other files, organised in a pre-defined way to facilitate reuse and share.
Play: a provisioning executed from start to finish is called a play.
Facts: global variables containing information about the system, like network interfaces or operating system.
Handlers: used to trigger service status changes, like restarting or reloading a service.