And a hamburger isn't a "sandwich", it's a "burger". But these distinctions aren't universal. It's easy to see why some people call pizzas pies if you look at

And a hamburger isn't a "sandwich", it's a "burger". But these distinctions aren't universal. It's easy to see why some people call pizzas pies if you look at variants like "deep pizza" (or "Chicago style pizza"). Essentially you might as well argue whether it's "soda" or "pop".