What is micro wave?

Answer 1

the microwave is a wavelength of light beyond the human visible spectrum.

the full spectrum of light as known by current science from smallest wavelength to longest is; y rays, x rays, UV (ultraviolet), the visible spectrum, infra red, micro waves, radio waves (including FM and AM frequencies), and long radio waves

so a microwave is a wavelength of light longer then infra red, and shorter then radio waves.