Two convergent and complementary approaches. Many scientists consider the zone is more precisely define by 1-100 nm.
In the "nano" zone, classical and quantum mechanics partially govern traditional disciplines (physics, chemistry and biology).
Nanotechnologies applied to various sectors such as Materials, Information or Health Technologies and concern designing, characterization, production and application of structures, devices and systems at the nanoscale. We can distinguish "top-down" approach (from micro towards “nano”) from "bottom up" approach (from molecule towards “nano”).