I don't think there's a single easy definition of "Staff Engineer" and it's usually just a title. But it might be still good to think about why those folks keep talking about this specific title.
From my observation, there is a certain inflection point in a senior level engineer's career where their expectation rapidly grows in that no one can realistically match it alone. The quality of your work will saturate and it's physically impossible to "work harder". Some extraordinary engineers could delay that point a bit but they will be eventually there.
At the moment, they will need to figure out a consistent, reproducible way to scale their contribution. If they want further career progression. The most direct way is becoming an engineering manager. Someone may develop a technical and organizational skill to influence high level decisions and prioritization. Or just become an engineering genius...
There are many other possible ways to achieve this, but the point is that further contribution at this point usually needs a radically different way. I do see that many companies tend to grant a title of "Staff Engineer" to those folks able to figure out how to handle this situation.
From my observation, there is a certain inflection point in a senior level engineer's career where their expectation rapidly grows in that no one can realistically match it alone. The quality of your work will saturate and it's physically impossible to "work harder". Some extraordinary engineers could delay that point a bit but they will be eventually there.
At the moment, they will need to figure out a consistent, reproducible way to scale their contribution. If they want further career progression. The most direct way is becoming an engineering manager. Someone may develop a technical and organizational skill to influence high level decisions and prioritization. Or just become an engineering genius...
There are many other possible ways to achieve this, but the point is that further contribution at this point usually needs a radically different way. I do see that many companies tend to grant a title of "Staff Engineer" to those folks able to figure out how to handle this situation.