Ask 100 people this question and you'll get 11 different answers; 90 people will say "I have no idea", and the other ten will give you varying definitions.
Lately we've been talking with a lot of people who have little awareness of nanotech, so we've had to answer the question many times. Here is CRN's preferred definition:
'Nanotechnology' is the engineering of functional systems at the molecular scale.* This covers current work and concepts that are more advanced.
In its original sense, nanotechnology refers to the projected ability to construct items from the bottom up, using techniques and tools being developed today to make complete, highly advanced products.
Based on Richard Feynman's vision of miniature factories using nanomachines to build complex products, advanced nanotechnology (sometimes referred to as molecular manufacturing) will make use of positionally-controlled mechanochemistry guided by molecular machine systems. Its best known exposition is in the books of K. Eric Drexler. Formulating a technology roadmap for its development is an objective of a broadly based "Productive Nanosystems" project led by Battelle (the manager of several U.S. National Laboratories) and the Foresight Institute.
Shortly after this envisioned molecular machinery is created, it will result in a manufacturing revolution, probably causing severe disruption. It also has serious economic, social, environmental, and military implications.
When Eric Drexler popularized the word 'nanotechnology' in the 1980's, he was talking about building machines on the scale of molecules, a few nanometers wide -- motors, robot arms, and even whole computers, far smaller than a cell. Drexler spent the next ten years describing and analyzing these incredible devices, and responding to accusations of science fiction. Meanwhile, mundane technology was developing the ability to build simple structures on a molecular scale. As nanotechnology became an accepted concept, the meaning of the word shifted to encompass the simpler kinds of nanometer-scale technology. The U.S. National Nanotechnology Initiative was created to fund this kind of nanotech; their definition includes anything smaller than 100 nanometers with novel properties.
Nanotechnology is often referred to as a general-purpose technology. That’s because in its mature form it will have significant impact on almost all industries and all areas of society. It offers better built, longer lasting, cleaner, safer, and smarter products for the home, for communications, for medicine, for transportation, for agriculture, and for industry in general.
Like electricity or computers before it, nanotech will offer greatly improved efficiency in almost every facet of life. But as a general-purpose technology, it will be dual-use, meaning it will have many commercial uses and it also will have many military uses -- making far more powerful weapons and tools of surveillance. Thus it represents not only wonderful benefits for humanity, but also grave risks.
A key understanding of nanotechnology is that it offers not just better products, but a vastly improved means of production. A computer can make copies of data files -- essentially as many copies as you want at little or no cost. It may be only a matter of time until the manufacture of products becomes as cheap as the copying of files. That’s the real meaning of nanotechnology, and why it is sometimes seen as “the next industrial revolution”.
In practical terms, most people will encounter nanotech through an apparently simple device called a nanofactory that may sit on your countertop or desktop. Packed with miniature chemical processors, computing, and robotics, it will produce a wide-range of items quickly, cleanly, and inexpensively, all controlled by a touch screen. Nanotechnology not only will allow making many high-quality products at very low cost, but it will allow making new nanofactories at the same low cost and at the same rapid speed.
This unique (outside of biology, that is) ability to reproduce its own means of production is why nanotech is said to be an exponential technology. It represents a manufacturing system that will be able to make more manufacturing systems -- factories that can build factories -- rapidly, cheaply, and cleanly. The means of production will be able to reproduce exponentially, so in just a few weeks a few nanofactories conceivably could become billions. It is a revolutionary, transformative, powerful, and potentially very dangerous -- or beneficial -- technology.
How soon will all this come about? Conservative estimates usually say 20 to 30 years from now, or even later. However, CRN is concerned that it may occur much sooner, quite possibly within the next decade. This is because of the rapid progress being made in enabling technologies, such as optics, nanolithography, mechanochemistry and 3D prototyping. If it does arrive that soon, we may not be adequately prepared, and the consequences could be severe.
We cannot say with certainty that full-scale nanotechnology will not be developed with the next ten years, or even five years. It may take longer than that, but prudence -- and possibly our survival -- demands that we prepare now for the earliest plausible development scenario.
*Definition updated on March 17, 2006.