is that the little black box with male/female connectors and the little ground wires leading out?

Depends on the system and on what you're talking about.

A ground loop isolator is a third party device (a black box with RCA leads) that goes inline between the amp and the head unit to remove a ground loop between the two.

A ground lift is a feature built into some amplifiers which deliberately disconnects the RCA ground shields from the amplifier's chassis ground.

edit: To clarify. A ground loop isolator is not the same thing as a ground lift. It's feasible that either one of these things could be built into a black box with RCA leads, but they have two completely different functions. The former separates all electrical connections on the RCA leads between the head and amp while still providing a method for the audio signal to be sent down the wire. A ground lift simply disconnects the shields while leaving the center pin untouched.