Firstly, what exactly is Thanksgiving? It comes from orgins dating back as far as 1609 from a group of Puritans fleeing religious prosecution in England. These Puritans boarded the familiar ship you most likely know the name of, the Mayflower. They settled into a New World and made peace with local American indians who helped them with a successful harvest. Historians believe the feast was held sometime in fall, and not with the traditional turkey but more likely fish and venison. It was an important union between the natives and the settlers, one that only lasted 50 years before more blood was shed between the different cultures.
Thanksgiving in other cultures, much like the American culture, symbolizes harvest. For example, do you remember in kindergarten coloring a cornucopia? It was that horn shaped basket filled with things that you found in Autumn like pumpkins, corn, squash, and also fruits and vegetables, hence the meaning harvest. As a kid, you didn't know much about what you were coloring besides the fact that you had to stay in the lines, or that you colored it around Thanksgiving.
Interestingly enough, the cornucopia comes to us from the ancient Greeks and Romans, the Latin word cornu copiae meaning horn of plenty. In fact, the ancient Greeks celebrated a three day festival of harvest in tribute to the goddess Demeter who symbolized corn and grains. The Egyptians also participated in a harvest festival dedicated to Min, the god of vegetation and fertility.
The Chinese harvest festival called Chung Ch'ui is in honor of the harvest moon. Like the turkey symbolizes traditional American Thanksgiving round yellow cakes were the center of the feast for Chinese families called moon cakes. In the Jewish culture Sukkot is celebrated. A Sukkot is a hut of branches where Jewish families eat under the night sky for for eight days. Thanksgiving is not just an American holiday, in fact, there are different Thanksgiving type celebrations and customs renowned around the world.