English
Euroregion
From Euro- + region.
Proto-Indo-European *h₃reǵ- ‘to straighten’
…
Latin regō ‘to rule’
Latin regiō ‘direction’
Anglo-Norman regiun
Middle English regioun ‘a realm’
English region
Today it means
noun A transnational cooperation structure, usually without political power, between contiguous territories located in different European countries.
Language periods are conventional ranges, not dates for this word.
Etymograph / Euroregion