A dipped Italian beef is the same sandwich as a plain one right up until the second the assembled roll, beef and all, goes back into the jus and stays there. That submersion is the entire order. A standard beef is dipped briefly, cut side down, so only the crumb takes on liquid; the dipped, sometimes called wet or soaked, goes in whole and comes out with the crust itself saturated through to the outside. The decision being made is not how much flavor to add but how close to total structural failure the eater wants the bread delivered. A dipped beef arrives one notch short of dissolving, and that is the point of asking for it.
The craft is in reading the saturation point and serving against it. The roll has to start as a sturdy length of Italian bread, because anything softer turns to paste the moment it is fully bathed, and even the right roll has a narrow window: too brief a dip and it is just a wet beef, too long and the loaf collapses in transit before it reaches the hand. The beef underneath is sliced against the grain as thin as a deli blade will take it, so the meat stays tender inside a roll that is now barely holding. The jus is seasoned to be the dominant flavor, since at this level of soak every part of the sandwich tastes of it and nothing else gets a vote. The counter, hot giardiniera or sweet peppers, becomes more structural here than on a dry order, because the chopped vegetables are the only firm thing left and the acid is the only relief from a sandwich that is otherwise all salt and softness. The Chicago counter built its grammar around exactly this threshold: how wet, and whether it goes back in one last time before it is wrapped, which is the difference between a sandwich and a plate eaten standing up, fingers stained, leaning forward so it lands on paper instead of shoes.
The dipped order sits next to the combo, which folds an Italian sausage in alongside the beef and adds a second protein to manage, and the plain dry build, which keeps the same parts but stops the soak at the crumb. Both stay inside the wet-roll family and both have rules of their own that deserve their own articles rather than being crowded in here.