doohickey

noun

1. (slang)A thing (used in a vague way to refer to something whose name one does not know or cannot recall)

   “What does this doohickey do?”

   “Customers will ask for "gizmos" and "what-cha-ma-call-its" and "doohickeys," and make crude drawings on paper bags of what it is they think they need.”

   “Besides, the show has invented a doohickey that makes it possible for Dr. Manhattan to exist as Calvin, a stable and supportive husband and father with no memory of his life as Jon Osterman, who can live out those 10 years as something close to a human being.”