A greek souvlaki is actually a specially marinated lamb wrapped in greek souvlaki bread with lettuce, tomato, onion and garlic sauce. Meat on a skewer is something else entirely.

I went searching for a recipe for the garlic sauce for souvlaki (also known as yiros and kebabs in other cultures - same dish) and found many U.S. references to pork or chicken on a skewer. Souvlaki apparently translates as "made of lamb".