(also eight-hundred-pound gorilla or nine-hundred-pound gorilla) A powerful force; a virtually irresistible influence: She is a 600-pound gorilla. She can intimidate anybody/ likens Spielberg to an ''800-pound gorilla,'' which can be defined as a high-priced Hollywood species that makes its own decisions/ There were no obvious 900-pound gorillas like Forrest Gump or Schindler's List
[1970s+; fr a joke in which the question ''Where does a six-hundred-pound gorilla sleep?'' is answered ''Anywhere it wants'']