
1) Two-ply molecular structure
Found on
https://www.crosswordclues.com/clue/bilayer

A bilayer is a double layer of closely packed atoms or molecules. The properties of bilayers are often studied in condensed matter physics, particularly in the context of semiconductor devices, where two distinct materials are united to form junctions (such as p-n junctions, Schottky junctions, etc.). In biology a common example is the Lipid bilay...
Found on
http://en.wikipedia.org/wiki/Bilayer

(bi´la-әr) a membrane consisting of two molecular layers, such as the cell membrane or the envelope of some viruses. Lipid bilayer, a fluid barrier to permeability, with polar head groups exposed and hydrophobic tails sequestered.
Found on
http://www.encyclo.co.uk/local/21001

a structure composed of two molecular layers, esp. of phospholipids in cellular membranes.
Found on
https://www.infoplease.com/dictionary/bilayer
No exact match found.