William Henry Pratt was an English actor who worked in Hollywood. He was born on November 23, 1887, in London, England. He was popularly known by his stage name Boris Karloff, which was a combination of the first and last names of his friends. However, some other synonyms for the name "William Henry Pratt" may include names such as Willy Pratt, Liam Hank, Bill Henry, Hank William, Will Harp, etc. Although Boris Karloff was the name he was most commonly known by, it is interesting to note that he had a few other names he could have gone by if he had so chosen.