Gyros (also gyro) is the traditional Greek street food. Some people call it "Greek sandwich" and it may be compared to the Turkish doner kebab. It consists of seasoned chopped meat (pork or chicken), French fries, tomatoes, onion, sauce and flat pita bread. There may be slight variations, mostly in the sauce type - mustard, tomato or tzatziki sauce, but overall it is the most common spread.
Gyros, along with the "crepes" (meaning pancakes but this is another story), is the main type of fast food you will come across everywhere in Greece and especially in small settlements and resorts. It is easy to find - you will recognize it by the big rotating spits with skewered meat. You can have it as take-away food but you can also eat it on the spot, as usually all places which sell gyros function as small restaurants and you can order salads, appetizers, drinks or other meals as well. When the meat and all the other ingredients are wrapped in the pita bread, it is called "gyros pita" - the take away type. The other type, "gyros merida", is always served in a plate with all ingredients arranged, and the pita bread comes separately or sidelong.
Would be good to keep in mind that:
1. Gyros pita is always one size - big. Certainly the size and quantity vary from place to place but one gyros is usually enough to feed a very hungry person. Eating two gyros pitas at once may be challenging...and heavy.
2. Gyros merida is bigger than gyros pita and it has more meat and fries. Sometimes it can feed two hungry persons, again depending on the place.
3. Prices for the pita type range from EUR 2.30 to 3.50, and the plate type is approximately EUR 7-8 or more.