Federal Aviation Administration Draft Advisory Circular 150/5360-14A, Access to Airports by Individuals with Disabilities

1.6.18 Terminal.
For the purposes of this AC, a terminal is a distinct area common to and prior to any Transportation Security Administration (TSA) checkpoint, or a distinct sterile area common to and beyond one or more TSA checkpoints. Each non-sterile area that is housed in a separate building is considered a separate terminal, and any sterile area that can be accessed only through a specific checkpoint or checkpoints is considered a separate terminal.