The basic ingredients of pastry doughs, which are used to make both sweet and savory pies and tarts, are flour, oil, and water. Some versions may add sugar, eggs, cream cheese, or milk. To prevent the production of gluten in the flour, which would produce a stiff crust, they are barely combined.
It also refers to a class of baked pastries, such as those you buy with your morning coffee, but it specifically refers to a sort of dough, such as the one used to create pies, tarts, and quiche.