Nanotechnology is an often misunderstood term. Say the word, and you are likely to elicit various conceptions from complete ignorance of the term to the fear of a science fiction type mass assembler that threatens the world. 2 The term has come to mean different things to different people. “Nano” is a prefix meaning one-billionth. In distance, a nanometer is one billionth of a meter. As illustration, a human hair is 100,000 nanometers (nm) in width. A red blood cell measures approximately 5,000 nm across. Ten hydrogen atoms, lined up side by side, if.