"white whale." YourDictionary, n.d. Web. 17 August 2018. <http://www.yourdictionary.com/white-whale>.
white whale. (n.d.). Retrieved August 17th, 2018, from http://www.yourdictionary.com/white-whale
(plural white whales)
From white +"Ž whale. Figurative and additional senses derive from reference to Herman Melville's 1851 novel Moby-Dick, in which Captain Ahab relentlessly pursues an albino sperm whale.