Souvlaki Apo Gyro (Thessaloniki) is a piece of local vocabulary in physical form. In Thessaloniki the counter word souvlaki covers the wrapped street meal generally, so to specify the rotisserie meat, the vertical cone the rest of Greece calls gyros, you ask for it apo gyro, "from the gyros cone." The phrase tells the cook to shave from the spit rather than pull pieces off a skewer. For anyone trained on Athenian usage, where gyros and souvlaki name clearly separate things, this is the inversion that has to be learned before the order makes sense.
What you get under this name is rotisserie meat in pita. The cone is stacked, seasoned, and turned against a vertical heat source so the outer layer crisps; the cook shaves that crisped edge off in thin strips straight into warm flatbread, then folds in the accompaniments. The build runs in order: the pita warmed and made pliable, the freshly shaved meat hot off the cone, then the vegetables and sauce. Good execution is shavings taken from a properly crisped exterior so each strip has browned edges and juicy interior, packed into a pita that holds its shape. Sloppy execution is meat sliced from an undercooked cone so it is pale and limp, shavings cut early and left to go cold and grey, or a tired pita that splits, plus the regional hazard that a kitchen misreading the order serves the skewered meat instead, which is exactly the confusion apo gyro is meant to settle.
This is a naming distinction, not a separate recipe. The rotisserie meat itself is the same as gyros anywhere in Greece; the only thing particular to Thessaloniki is that you must say apo gyro to get it. Its paired term is apo kalamaki, "from the skewer," the local phrase for the skewered meat, which stands on its own rather than being crowded in here. The full Thessaloniki versus Athens naming swap, where souvlaki and gyros trade meanings, deserves its own article. What this entry pins down is one specific phrase: how, in the north, you ask for the meat shaved from the cone and make sure the cook reaches for the spit and not the stick.