The NEC already made it clear for this one for its own purposes: They are called service drops if upstream of the service point, and overhead service conductors if downstream of the service point and upstream of the service-entrance conductors. For underground installations, they are called service laterals if upstream of the service point, and underground service conductors if downstream of the service point. Since underground installations may or may not have a service-entrance conductor, the underground service conductor ends at either the service-entrance conductors or directly at the service equipment. For purposes outside of the NEC, you can call them whatever you want, but this question asked about the NEC only.