superstratum

[soo-per-strey-tuh m, -strat-uh m, soo-per-strey-tuh m, -strat-uh m] /ˈsu pərˌstreɪ təm, -ˌstræt əm, ˌsu pərˈstreɪ təm, -ˈstræt əm/
noun, plural superstrata
[soo-per-strey-tuh, -strat-uh, soo-per-strey-tuh, -strat-uh] /ˈsu pərˌstreɪ tə, -ˌstræt ə, ˌsu pərˈstreɪ tə, -ˈstræt ə/ (Show IPA), superstratums.
1.
an overlying stratum or layer.
2.
Historical Linguistics. a set of features of a language traceable to the influence of a language formerly spoken within the same society by a dominant group:
English has a Norman-French superstratum.
Compare substratum.
Origin
1800-10; super- + stratum; cf. substratum
British Dictionary definitions for superstratum

superstratum

/ˌsuːpəˈstrɑːtəm; -ˈstreɪ-/
noun (pl) -ta (-tə), -tums
1.
(geology) a layer or stratum overlying another layer or similar structure
2.
(linguistics) the language of a conquering or colonizing population as it supplants that of an indigenous population, as for example French and English in the Caribbean Compare substratum (sense 8)