Nanotechnology – study of physical phenomena on the nanoscale, dealing with things measured in nanometres, billionths of a meter. Nanotechnology is a complex scientific area involving the rearrangement of atoms at a molecular level, i.e. creating devices at a molecular level. Atomic rearrangement depends on the material used because any alteration of the atoms changes the identity of the material. Nanotechnology is rearranging atoms to create things at an extremely small scale, and it was popularized by Eric Drexler: "Eric Drexler was the godfather of nanotechnology." In 1977, Drexler had the idea of creating tiny robots that were able to manipulate molecules and produce any substance in a very small amount of time. He was the spark that started nanotechnology research. Nanotechnology has come a long way from 1977 to today.
Green nanotechnology – use of nanotechnology to enhance the environmental-sustainability of processes currently producing negative externalities. It also refers to the use of the products of nanotechnology to enhance sustainability.
Ceramic engineering – science and technology of creating objects from inorganic, non-metallic materials.
Materials science – interdisciplinary field applying the properties of matter to various areas of science and engineering. It investigates the relationship between the structure of materials at atomic or molecular scales and their macroscopic properties.
Nanoarchitectonics – arranging nanoscale structural units, which are usually a group of atoms or molecules, in an intended configuration.
Grey goo – hypothetical end-of-the-world scenario involving molecular nanotechnology in which out-of-control self-replicating robots consume all matter on Earth while building more of themselves, a scenario known as ecophagy ("eating the environment"). Grey goo consists of devices that could potentially be able to make copies of themselves repeatedly without control from the creator. In other words, an uncontrollable, self-replicating nano-machine or robot. The concept of grey goo is largely similar to the vast amount of science-fiction movies that involve self-replicating robots taking over the world. These are science-fiction movies because they are not based on anything real, but this potential outbreak of self-replicating robots has become a reality through the research of nanotechnology. The term grey goo was devised by Eric Drexler in one of his many books. Eric Drexler knew that grey goo could be extremely dangerous and could potentially take over everything if scientists did not know what to do to stop them. He said, "Dangerous replicators could easily be too tough, small, and rapidly spreading to stop — at least if we made no preparation." In Chris Phoenix and Eric Drexler's paper "Safe Exponential Manufacturing" they state that grey goo cannot be produced through the software programs used for nanotechnology. They say, "The development and use of molecular manufacturing need not at any step involve systems that could run amok as the result of accident or faulty engineering."
People such as state agencies, criminals and enterprises could use nanorobots to eavesdrop on conversations held in private.