It is hard to say in writing. In the United States you just buy a measuring cup at the store and it will have a line that says one cup. It is actually a certain amount. Or a measuring cup that is one cup, you fill it up to the top. If you had a cup that is round with a flat bottom and sides that go straight up and don't slant in wards as it goes down to the bottom. It would be like 2 inches high and 2 inches in diameter. There are 5.08 centimeters in 2 inches.
