Gelatin is an edible thickener that's made from finely ground animal bones and tissue. It's gelatin that gives marshmallows and Jell-o their thick, gummy texture.
While you're probably familiar with gelatin in gummy bears, candy corn, and other sweets, it's also commonly used in foods like cream cheese, low fat yogurt, and some Chinese dumplings. There are non-food uses for gelatin as well, including glue, medicine, sandpaper, and makeup. Gelatin isn't vegetarian — it's made from animal parts, including bones and connective tissue. Gelatin comes from the French gélatine, "jelly-like substance from animals," and its Latin root meaning "to congeal."