A domain starts out as a blank canvas. Probably like an architect sees an empty plot of land at a specific address in an existing neighborhood.
A website is like a house or a business built on that land.
A domain’s “neighbors” are other similar domain names, and also those websites returned by search engines by typing in those (or related) words.
So for example, a Google search for “every american” shows the current virtual neighborhood for this domain. Like any other neighborhood, the nearby properties (domains and websites) are always changing.