Ok, this is starting to frustrate me.. so:
Definition of PIZZA
:
a dish made typically of flattened bread dough spread with a savory mixture usually including tomatoes and cheese and often other toppings and baked —called also pizza pie
Source:
https://www.merriam-webster.com/dictionary/pizza
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OR
pizza
noun
a baked Italian
dish consisting of flattened bread dough covered variously with herbs, fresh vegetables, or, typically in the U.S., with tomato sauce, grated cheese, and, often, sausage, mushrooms, pepperoni, etc.
Source:
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
Used by arrangement with John Wiley & Sons, Inc.
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Lastly:
veg·e·ta·ble adj \ˈvej-tə-bəl, ˈve-jə-\
Definition of VEGETABLE
1
a : of, relating to, constituting, or growing like plants
b : consisting of plants : vegetational
2
: made from, obtained from, or containing plants or plant products <vegetable soup> <vegetable fat>
3
: resembling or suggesting a plant (as in inertness or passivity)
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Can we now wrap up this discussion? Arguing what the condiments consist of wont necessarily change what it essentially is, or its history.
Pizza is essentially a dish with a wheat/ bread base with a topping and, usually (but not always,) a sauce to accompany it. It's why people can define other dishes rice that is fried with an assortment of fish overtop a "sushi pizza" for example. The dish can be made many ways.