Mesoscopic refers to the size scale between microscopic (very small) and macroscopic (visible to the naked eye) in physics and materials science. It typically involves systems that are larger than individual atoms or molecules but still exhibit quantum mechanical properties. Examples of mesoscopic systems include quantum dots, nanowires, and certain biological structures.
Pier A Mello has written: 'Quantum transport in mesoscopic systems' -- subject(s): Quantum theory, Maximum entropy method, Mesoscopic phenomena (Physics), Transport theory, Scattering (Physics)
JOHN WEINER has written: 'COLD AND ULTRACOLD COLLISIONS IN QUANTUM MICROSCOPIC AND MESOSCOPIC SYSTEMS'
Helmut Hofmann has written: 'The physics of warm nuclei' -- subject(s): Nuclear physics, Mesoscopic phenomena (Physics)
Ping Sheng has written: 'Introduction to wave scattering, localization, and mesoscopic phenomena' -- subject(s): Localization theory, Scattering (Physics), Waves
The size in at least one of the spatial dimensions should be in between the size of an individual atom (~0.1nm) and the electronic coherence length, ie. the maximum distance at which it makes sense to describe an electron with a single wavefunction. The coherence lenght is limited by inelastic processes, it depends strongly on the material, temperature, magnetic field, or even geometry of the device. In semiconductors at sub-Kelvin temperatures it can be of order of microns.