What is nanotechnology?

Nanotechnology is the technology of building devices, such as electronic circuits, from single atoms and molecules. Nano means "small", of the order 10-9m, so nanotechnology is (among other things) generally a conversation about new science that creates machines the size of molecules.
a technology executed on the scale of less than 100 nanometers, the goal of which is to control individual atoms and molecules, especially to create computer chips and other microscopic devices.

Nanotechnology is a term for devices and chemicals engineered at the nanometer scale. Broadly, it encompasses two separate ideas:
"Molecular nanotechnology" is the assembly of structures to complex, atomic specifications by means of mechanosynthesis.

"Nanoscale materials" encompasses any manipulation of matter at lengths from 1 to 100 nm, but often includes things on the micrometer scale.

Nanotechnology refers to the smallest scale of the engineering, not necessarily the size of the finished product.
Nanotechnology (sometimes shortened to "nanotech") is the manipulation of matter on an atomic and molecular scale. The earliest, widespread description of nanotechnology[1][2] referred to the particular technological goal of precisely manipulating atoms and molecules for fabrication of macroscale products, also now referred to as molecular nanotechnology. A more generalized description of nanotechnology was subsequently established by the National Nanotechnology Initiative, which defines nanotechnology as the manipulation of matter with at least one dimension sized from 1 to 100 nanometers. This definition reflects the fact that quantum mechanical effects are important at this quantum-realm scale, and so the definition shifted from a particular technological goal to a research category inclusive of all types of research and technologies that deal with the special properties of matter that occur below the given size threshold. It is therefore common to see the plural form "nanotechnologies" as well as "nanoscale technologies" to refer to the broad range of research and applications whose common trait is size. Because of the variety of potential applications (including industrial and military), governments have invested billions of dollars in nanotechnology research.

nano refers to something that is of the order 10-9. A nano-meter is therefore a very small unit of length. Nano technology refers to very small machines, small enough to work at a cellular or even molecular level. Check out the SF story Blood Music by Greg Bear.
Nanotechnology is the the branch of technology that deals with dimensions and tolerances of less than 100 nanometers, esp. the manipulation of individual atoms and molecules. (The definition from my dictionary) In my words, Technologies that deal with how things behave when they are very small. VERY small. A nanometer (nm) is one BILLIONTH of a meter. Wow! One strand of hair is about 100,000 nm. For more information, vist http://www.futureforall.org/nanotechnology/nanotechnology.htm I hope this is what you were looking for!