Shadrach is the name of one of the three Jewish exiles that was thrown in the fiery furnace by Nebuchadnezzar for not praying to an idol. His Jewish name is actually Hananiah.
Though used by Christians and Jews in recent times because of its Biblical heritage, Shadrach is a Babylonian name, and means "command of Aku". Aku was the ancient Babylonian moon god, the equivalent of the Assyrian god Sin. Though rare today, and never particularly common, Shadrach was used as a first and last name in the early-to-mid 19th century. A shortened form for casual use was "Shad".