When applied to physical phenomena and bodies, the macroscopic scale describes things as a person can directly perceive them, without the aid of magnifying devices.
This is in contrast to observations (microscopy) or theories (microphysics, statistical physics) of objects of geometric lengths smaller than perhaps some hundreds of micrometres.
Not quite by the distinction between macroscopic and microscopic, classical and quantum mechanics are theories that are distinguished in a subtly different way.
Roughly speaking, classical mechanics considers particles in mathematically idealized terms even as fine as geometrical points with no magnitude, still having their finite masses.
Near the absolute minimum of temperature, the Bose–Einstein condensate exhibits effects on macroscopic scale that demand description by quantum mechanics.
The related correspondence principle can be articulated thus: every macroscopic phenomena can be formulated as a problem in quantum theory.
Intuitively, it might seem incorrect to associate "high energy" with the physics of very small, low mass–energy systems, like subatomic particles.
By comparison, one gram of hydrogen, a macroscopic system, has ~ 6×1023 times[4] the mass–energy of a single proton, a central object of study in high energy physics.