mesoscope

mes·o·scope

(mez'ō-skōp),
An instrument for viewing objects that are larger than microscopic but cannot be seen distinctly with the unaided eye.
[meso- + G. skopeō, to view]

mesoscope

An obsolete term for an instrument formerly used to view objects between macroscopic and (light) microscopic resolutions; e.g., dissecting microscopic.