Souvlaki Apo Kalamaki (Thessaloniki) is a naming convention as much as a dish. In Thessaloniki the word souvlaki on a counter sign points to the rotisserie meat that the rest of Greece calls gyros, so to order skewered meat in a pita you ask for it apo kalamaki, "from the skewer." The phrase exists to disambiguate. Kalamaki is the thin wooden skewer; specifying apo kalamaki tells the cook you want the threaded, charcoal-grilled pieces rather than the shaved cone. For anyone used to Athenian terminology this inversion is the first thing to understand about ordering in the north.
What lands in the pita under this name is standard skewered souvlaki: small pieces of meat, usually pork, grilled on the kalamaki over charcoal, then slid off into warm flatbread. The build is the familiar one. The pita is warmed and made pliable, the meat comes off the stick hot with char on its faces and a juicy interior, and the usual accompaniments are folded in. Good execution is the same standard any souvlaki is held to: evenly cut cubes, deep browning, a pita that holds without tearing, the components balanced. Sloppy execution is the same failure set, dry overcooked meat, a cold split pita, sauce piled to drown the rest, with the regional wrinkle that a kitchen confused by the order might hand you the rotisserie meat instead, which is the precise mistake the phrase apo kalamaki is meant to prevent.
The distinction is entirely linguistic and regional, not a different recipe. The skewered meat itself is the same souvlaki sold across Greece; what changes in Thessaloniki is only the vocabulary you need to get it. Its mirror term is apo gyro, "from the gyros cone," the local way to ask for the rotisserie meat, and that rotisserie form deserves its own article rather than being crowded in here. The broader Thessaloniki versus Athens naming question, where souvlaki and gyros swap meanings, is a topic in its own right. What this entry marks is one specific phrase: how, in the north, you ask for the meat on the stick and make sure that is what you get.