The term “ nanoscale science and technology” (N S & T) refers to the understanding and controlled manipulation of structures and phenomena that have nanoscale dimensions. Scientists have adopted the Greek word nano as a prefix to mean one billionth of a unit of measure. So a nanosecond is one billionth of a second, a nanometer (nm) is one billionth of a meter (m), etc.

The nanoscopic scale usually refers to structures with a length scale applicible to nanotechnology , usually cited as 1-100 nanometers. The nanoscopic scale is roughly speaking a lower bound to the mesoscopic scale for most solids.
Source: Wikipedia