What does ray stand for?

Answer 1

xerography was what I was always told whenever I asked

ANS2:The name "x-ray" was applied to radiation in the same frequency as gamma radiation but which originate from a man-made source. See the link for the rest of the story from which the following quote was taken.

A week after his discovery, Röntgen took an X-ray photograph of his wife's hand which clearly revealed her wedding ring and her bones. The photograph electrified the general public and aroused great scientific interest in the new form of radiation. Röntgen named the new form of radiation X-radiation (X standing for "Unknown"). Hence the term X-rays (also referred as Röntgen rays, though this term is unusual outside of Germany).