Network/Connectivity Modules
This is maybe what you would think of as a traditional RF modules. These modules act as pure modems handling the wireless communication and offer your application control and communication through a pre defined serial interface. These modules add a wireless interface for your new or existing application, but will require you to include module specific SW libraries to your code base.
nRF8001 Modules
Source: https://www.nordicsemi.com/eng/Products/3rd-Party-Bluetooth-low-energy-Modules