chicken ?
The original Wiener Schnitzel is pan-fried, breaded veal. The veal is cut rather thin and first put into flour, then eggs and finally breadcrumbs. This coating is much better that any batter, IMO. Finally it's fried in a pan. A Wiener Schnitzel of proper size must not fit the plate it is served on.
There are many variations, e.g. using pork, chicken, or turkey. You can also put cheese and ham between two layers of meat before breading (called "Cordon Bleu"). The one in the picture is actually a pork cordon bleu.
Originally it's not an Austrian dish, it's from Italy where it is called "Piccata Milanese".