What is the meaning of Regio?

Any large area of a planet or moon that is strongly differentiated from neighbouring areas by colour or albedo.

A district of a city.

region

region: a place in or a part of the body in any way indicated.

royal

grand, excellent

direction, line

boundary line, boundary

region, district, province

ground

sphere, department

opposite, on the other side (e + regione + genitive or dative)

royal, regal

stupendous

Monterreyan, born in Monterrey, clipping of regiomontano

Source: wiktionary.org