Robert Van de Graaff was an American physicist who invented the Van de Graaff generator, a device that accumulates and produces high voltages. Synonyms for Robert Van de Graaff include "physicist," "inventor," and "scientist." He was also a professor of physics at Princeton University, so "academic" or "educator" can also be used. Moreover, Van de Graaff was a pioneer in the field of nuclear physics, so "nuclear physicist" could be added. Overall, Robert Van de Graaff is a vital figure in the world of science and physics, and his contributions continue to influence and inspire future generations of scientists.