double-layer

The word "double-layer" is a modern English compound formed by combining two independent words of distinct origins. "Double" traces back to Latin duplus, itself from duo (two) and -plus (fold), entering English via Old French. "Layer" originates from the Middle English agent noun related to the verb "to lay," implying something that is laid down. The compound logically marries the quantitative concept of "twofold" with the structural concept of a "stratum," creating a transparent descriptor for any material or system composed of two distinct superimposed sheets or levels, commonly used in contexts from clothing and cooking to physics and electronics.

Structure: double (twofold) + layer (stratum) - double: From Latin duplus (twofold, double). In this compound, it functions as a quantifying prefix meaning "consisting of two." - layer: From Middle English leyer, related to lay (to place). In this compound, it functions as the core noun meaning a sheet, thickness, or stratum of material.