pellicle

noun

1. A thin skin or film.
2. A cuticle, the hard protective outer layer of certain life forms.
3. The outermost layer of a mushroom; the skin of a mushroom cap; especially, a surface that is viscid and easily peels off.
4. A thin layer supporting the cell membrane in various protozoa.
5. The growth on the surface of a liquid culture.
6. A skin or coating of proteins on the surface of meat to be smoked, improving the surface adhesion.
7. A coating of glycoproteins from saliva that forms on teeth; it offers some protection to the enamel from bacterial acidity.
8. The photosensitive emulsion of photographic film.
9. A thin plastic membrane used as a beam splitter or protective cover (for example, to protect a photomask).