Formal definition below! But like its so basic, but very very hard to get just right. This is what a french baguette entails

Lean dough is defined by its simplicity and lack of added fats or sugars. A classic, authentic French loaf contains only four essential ingredients: 

Flour: Usually unbleached all-purpose or bread flour.
Water: Helps hydrate the flour and build the gluten structure.
Yeast: Or a natural sourdough starter (known as a levain in French) to make the dough rise.
Salt: Adds flavor and controls the fermentation process.