What is a nano-sized particle?

The classic definition often used in the scientific community is that a particle is considered to be nano-sized when it measures less than 100 nanometers in size. This particular definition serves as a non-limiting functional definition, which emerged when researchers and scientists made significant discoveries regarding the unique and remarkable properties exhibited by certain materials that possess nanometer-sized dimensions. These tiny particles often display behaviors and characteristics that are vastly different from their larger counterparts, leading to a deeper understanding of their potential applications in various fields such as nanotechnology, medicine, and materials science.