Gyros vs Souvlaki Terminology is an explainer entry, not a recipe: it exists to untangle the single most confusing thing about ordering Greek street food, which is that the same two words mean different things depending on the city. The angle is geographic. In Athens the distinction is clean and physical: souvlaki means skewered meat, the cubes grilled on a stick, while gyros means the rotisserie cone, the meat stacked on a vertical spit and shaved off. Ask for one and you get one; ask for the other and you get the other. The words track the cooking method.
In Thessaloniki the system collapses into a single label. There, effectively everything from the grill or the spit is called souvlaki, the skewered version and the shaved-cone version alike. A northern souvlaki might arrive as a wrap of spit-shaved meat that an Athenian would unambiguously call gyros, and locals will defend their usage with real intensity. The honest framing is that neither city is wrong inside its own borders; these are two parallel naming conventions, not a correct one and a mistake. The practical consequence for anyone ordering across regions is that the word alone does not tell you what arrives. In Thessaloniki you specify the form, the cone or the skewer, rather than trusting the noun, because the noun has been generalized; in Athens the noun still does the work. This is also why diaspora menus are often internally contradictory, since they inherit one city's habit and apply it everywhere.
The terminology shifts strictly by place, and the related questions branch off cleanly. How the word gyros itself is pronounced and what it shares with its rotisserie cousins is a separate matter that deserves its own article rather than being crowded in here, as does any particular regional build of the sandwich. The constant to carry away is narrow and useful: in Athens souvlaki is the skewer and gyros is the cone; in Thessaloniki souvlaki covers both, so when it matters, describe the cooking method rather than relying on the name alone.