A victual is anything that can be eaten. Victuals are food.
Victual is a fancy word for a very simple thing: any substance that can be used as food. Everything in the food pyramid is a victual, and whatever you eat for breakfast, lunch, dinner, and snacks are victuals. Words that apply to victuals are eatable and edible. A toddler eating a cigarette butt doesn't quite understand what's a victual and what's not.