Nanotechnology in fiction is when stories or movies use made-up science that involves tiny machines. These tiny machines are so small, they are called nanomachines or nanites. Nanomachines are able to do really cool things, like shrinking people down to tiny sizes so they can explore really small places like inside a human body. In some stories, nanomachines can fix things in the world, like repairing buildings and cleaning the environment. Nanomachines can also help create new worlds, like futuristic ones with amazing technology.