soap film

Short definition from Wiktionary

Noun

1. 1
   A film composed of soap; the wall of a soap bubble.
2. 2
   Any thin layer of liquid (usually water-based) surrounded by air, such as that formed when two soap bubbles come into contact; networks of such films (archetypally, soapy foams) have physical properties that are often mathematically predictable and serve as models.