Slightly off topic perhaps, but it's been my experience that these sorts of titles are meaningful and comparable only within a company. Across companies they don't mean much. A "principal" engineer at one company may not even be a senior engineer at another, or may be comparable to the CTO at another.

The terms are probably closer to being comparable within similar companies. e.g. the FAANG companies might have organically developed similar nomenclature to each other. But in general I find the terms are near-useless.

I wonder if others have the same impression. It would be nice if we had some way to calibrate positions across companies.