What is nano: It is a prefix a Greek word meaning midget or dwarf. In Science it means one in Billion in Mathematical term it is 10 power –9 of a meter, to atom level length of 10 hydrogen atoms.
Nanotechnology is the science behind to purposefully manipulate the matter to atom size in simple words it is engineering at a very small scale. Imagine Motors in the size of thumb nail, and even tiny seen only through microscope. All this are possible in coming years.
The above Image was written using Dip pen Nanolithography and images using lateral force microscopy of an atomic force microscope (Image courtesy Mirkin Group)
Nanoguitar (10 microns), 1997, courtesy of Dustin W.Carr and Harold G Craighead, Cornell Nanofabrication Facility and the School of Applied and Engineering Physics, Cornell University.
We have nano tech in our hands yes our mobile phone is product of nano technology. Nano has vast areas of use, our successors will be studying only through gadgets made out of nano tech in future.