How much money is considered rich in Boston?

I'm curious, what exactly constitutes being considered "rich" in the city of Boston? Is it a specific dollar amount, or is it more about the lifestyle and assets one possesses? I've heard that the cost of living in Boston can be quite high, so would the threshold for being considered wealthy be correspondingly elevated? Are there any notable differences in what is considered wealthy between different neighborhoods or social circles within the city? It would be interesting to gain a deeper understanding of this topic.