Cast Silver refers to the process in which molten silver is poured into a clay/plaster mold in order to create fine and intricate three dimensional designs on silverware which would otherwise be difficult.
Above : A Victorian solid silver fish server handle of a lady catching fish. (Click on image for product link).
The effects of "silver casting" present a distinct three dimensional design with the cast subject being highlighted and raised higher than usual and thus emphasizing certain elements within the overall design (in this case the handles of the fish servers).
The cast silver design is most often found in high end silverware with highly ornate and complex designs of wildlife, figures and plant based motifs.