superstrate

A layer or stratum adjacent and parallel to another.

(physics) The sudden increase in the electrical conductivity of some metals as their temperature falls to near absolute zero.

(photovoltaics) The covering on the sunny side of a photovoltaic (PV) module, providing protection for the PV materials from impact and environmental degradation while allowing maximum transmission of the appropriate wavelengths of the solar spectrum.

(linguistics) Alternative form of superstratum