William Herman Rapps (February 1, 1881 – April 20, 1965) was a professional baseball player whose career spanned 15 consecutive seasons, 1903 to 1917, in Minor League Baseball. He was known by several nicknames over his career, the most frequent being "Roaring Bill" for his boisterous on-field performance. Over his career, he played a number of positions, the most frequent being outfield and first base. In 1907, he was moved to second base and in 1914 became a backup catcher.