fox squirrel(n = noun.animal) eastern fox squirrel, sciurus niger - exceptionally large arboreal squirrel of eastern United States;
is a kind of tree squirrel
is a member of genus sciurus, sciurus

american flying squirrel, american red squirrel, antelope squirrel, arctic fox, arctic ground squirrel, asiatic flying squirrel, black fox, black squirrel, blue fox, cat squirrel, charles james fox, chipping squirrel, crab-eating fox, desert fox, douglas squirrel, eastern fox squirrel, eastern gray squirrel, eastern grey squirrel, flying fox, flying squirrel, fox, fox fire, fox grape, fox hole, fox hunter, fox hunting, fox river, fox shark, fox talbot, fox terrier, fox trot, gallant fox, george fox, gray fox, grey fox, ground squirrel, kid fox, kit fox, mantled ground squirrel, northern flying squirrel, parka squirrel, prairie fox, raccoon fox, red fox, red squirrel, richardson ground squirrel, rock squirrel, sea fox, silver fox, smooth-haired fox terrier, southern flying squirrel, spruce squirrel, squirrel, squirrel away, squirrel cage, squirrel corn, squirrel monkey, striped squirrel, tree squirrel, water fox, western gray squirrel, western grey squirrel, white fox, whitetail antelope squirrel, william henry fox talbot, wire-haired fox terrier