Merida Kebab is a portion word doing the work of a menu. Merida means a serving or a plate, so when a Greek grill lists merida kebab it is offering the kebab off the skewer and onto a plate rather than rolled into a pita. It is the same seasoned, char-edged ground or minced meat you would get wrapped to go, freed from the bread and given room to sit next to its accompaniments. The angle here is exactly that: this is the un-wrapped version, the one you eat with a fork at a table when you want the meat to be the center of the plate instead of one layer among five.
A proper merida is built like a small composed plate. The kebab comes off the grill and is sliced or left in lengths, then laid over or beside a folded grilled pita that has been brushed with oil and warmed on the same surface so it picks up smoke. Around it go the standard companions: a mound of tzatziki, raw onion cut thin, tomato wedges, sometimes a scatter of patates tiganites, the fried potatoes that would otherwise ride inside the wrap. Good execution shows in the meat first, juicy at the center with a real crust from the grill, seasoned through rather than only on the surface. The pita should be soft and pliable, not dried into a cracker by sitting too long on the heat. Sloppy versions arrive with grey, steam-cooked meat, a cold or stiff bread, and tzatziki that is thin and watery instead of thick enough to hold a spoon-shape.
The merida format scales cleanly. A merida for one is a single skewer's worth with its companions; a shared merida for a table is a heaped platter of mixed grilled meats, and at that point the kebab usually sits alongside souvlaki and other cuts so a group can graze. The bread stays a vehicle and a side rather than a wrapper, which is the whole point of ordering it this way. The skewer-and-pita street wrap, the souvlaki merida as its own plate, and tzatziki as a built condiment each shift the experience enough that they deserve their own articles rather than being crowded in here. What stays constant in every form is the trade you are making: you give up the portability of the wrap to get a hotter, more generous, more clearly tasted piece of grilled meat.