Here is a basic definition and some examples on how Nanotechnology works! Some examples include carbon atoms (nanotubes), batteries, assemblers, cells etc.
Here is a video where Ray Kurzweil a very well respected/well-known scientist and explains nanotechnology. Kurzweil wrote many books on the topic and he is an extreme activist on Nanotechnology. This video is about Ray Kurzweil Explaining The Future Of Nanotechnology: