The word "Jekyll" originates from the novel "Strange Case of Dr. Jekyll and Mr. Hyde" written by Robert Louis Stevenson and published in 1886. The character Dr. Jekyll is a scientist who creates a potion that transforms him into the evil and wild Mr. Hyde. The name "Jekyll" itself doesn't have a specific etymology, as it was invented by Stevenson for the purpose of the story. However, it is believed to be derived from the surname "Jeckyll", which was the last name of Colonel Philip Francis Jeckyll, a member of the Hyde Park committee in London who Stevenson may have encountered.