English

interregion

From inter- + region.

Proto-Indo-European *h₁én ‘in’

Proto-Indo-European *h₁entér ‘between’

Proto-Italic *n̥ter ‘between’

Latin inter ‘between’

Proto-Indo-European *h₃reǵ- ‘to straighten’

…

Latin regō ‘to rule’

Latin regiō ‘direction’

Anglo-Norman regiun

Middle English regioun ‘a realm’

Today it means

adj interregional

Language periods are conventional ranges, not dates for this word.

Etymograph / interregion