gelatin

noun

1. the tasteless, odorless, brittle mixture of proteins extracted by boiling skin, bones, horns, etc.; also, a similar vegetable substance: gelatin dissolves in hot water, forming a jellylike substance when cool, and is used in the preparation of various foods, medicine capsules, photographic film, etc.
2. something, as a jelly, made with gelatin
3. a sheet of translucent, colored material, placed over stage lights for special effects