What is the cable between the service panel and electric meter called?

Whether you have an overhead or underground feed, that section of the installation is referred to as Service Entrance Conductors. On an overhead installation, it includes the conductors on BOTH sides of the meter, from the service drop conductors (attached at the service head) to the service equipment LINE terminals. On an underground installation, it refers only to the conductors between the meter's LOAD side and the service equipment LINE terminals. The conductors on the LINE side of the meter come from a distribution transformer and are unbroken between the transformer and your meter.