Shepherd is a type label rather than a single breed. On adoption listings it most often means a German Shepherd or a German Shepherd mix, but it can also describe Australian, Belgian, Dutch or English Shepherds and crosses with Labs, Huskies and other dogs. What links them is ancestry in herding and flock-guarding work, where dogs moved, gathered and protected livestock.
Most are medium to large, athletic and quick to learn, with a thick shedding coat and a strong wish to stay near their people. Some are reserved or protective with strangers, and herding instincts can show up as nipping or chasing. They generally need daily exercise, training and a job to focus on. A home with a steady routine suits that well, and size, energy and coat vary a lot from dog to dog.