adstratum

[ ad-strey-tuh m, -strat-uh m ]
/ ˈædˌstreɪ təm, -ˌstræt əm /

noun, plural ad·stra·ta [ad-strey-tuh, -strat-uh] /ˈædˌstreɪ tə, -ˌstræt ə/. Historical Linguistics.

a substratum or superstratum.

Origin of adstratum