"Several unsatisfactory attempts have been made to etymologize the word Serapis. Godfrey Higgins notes that Soros was the name given by the Egyptians to a stone coffin, and Apis was Osiris incarnate in the sacred bull. These two words combined result in Soros-Apis or Sor-Apis, "the tomb of the bull." But it is improbable that the Egyptians would worship a coffin in the form of a man."
From The Secret Teachings of All Ages by Manly P. Hall. Page 57 of 633.