A dish in gastronomy is a specific food preparation, a "distinct article or variety of food", with cooking finished, and ready to eat, or be served.
A "dish" may be served on tableware, or may be eaten out of hand; but breads are generally not called "dishes".
Instructions for preparing a dish are called recipes. Some dishes, for example vanillaice cream with fudge sauce, rarely have their own recipes (and are not found in most cookbooks), as they are made by simply combining two ready to eat preparations of foods.
Many dishes have specific names (e.g.sauerbraten), while others are simply described ("broiled ribsteak"). Many are named for particular places, sometimes because of a specific association with that place like Boston baked beans or bistecca alla fiorentina. Sometimes not: poached eggs Florentine ends up meaning essentially "with spinach". Some are named for particular individuals, perhaps to honor them, or perhaps because the dish was first prepared for them, or perhaps they themselves invented the dish, or perhaps because the dish was invented in their kitchens; because of the high level of culinarymythology, it is often hard to tell the difference among these cases.