OBD stands for On-Board Diagnostics and it is an automotive term that refers to a vehicle's self-diagnostic and reporting capability. An OBD port is like a plug that allows diagnostic devices, such as Bouncie, to be inserted into your vehicle to monitor vehicle activity and diagnose issues. It's the same port that mechanics use to check to your vehicle when they assess it for issues.
Bouncie plugs an OBD2 port specifically to monitor your vehicle and driving data. OBD2 is the same thing as OBD-II as the terms are used interchangeably.