pellicle

noun

1. a thin skin or membrane; film; scum.
2. Photography. a thin, partially reflective coating, as on a beam splitter or pellicle mirror.

noun

1. a thin skin or film
2. the hard protective outer layer of certain protozoans, such as those of the genus Paramecium
3. botany
   1. the thin outer layer of a mushroom cap
   2. a growth on the surface of a liquid culture
4. photog the thin layer of emulsion covering a plate, film, or paper

n.1540s, from Middle French pellicle (Modern French pellicule), from Latin pellicula “small or thin skin,” diminutive of pellis “skin, leather, parchment, hide” (see film (n.)). Related: Pellicular. n.

1. A thin skin or film on the surface of a liquid.