DSc also stands for Doctor of Science, an advanced university degree
roughly equivalent to the Doctor of Philosophy degree. Like the PhD, the
DSc requires coursework, research, and ultimately the preparation of a
dissertation; as the name suggests, it's awarded only to students in the
sciences.
Many universities only award this degree honoris causa and give the
PhD to students who actually earned their degrees. Some schools in
Australia and New Zealand have an intermediate policy: they award the
degree only to alumni, who must present an application
demonstrating prominence and proficiency in their field.