What's a bush when it has no trees or shrubs?
What's an ocean when it has no water or sharks?
What's a house when it has no people or a family?
What's hunger when some people look for medicines to make them hungry?
Moreover, would the world be the world if there were no one on earth?

Would a woman be called a wife if not married?

I think everything on earth depends on something else to attain its name and recognition.
Moreover, you wouldn't be called a husband if you married none, would you?