Stellar Observation & Experimentally Demonstrated Explanatio

[Eutrophicated1]

For years, I've been reading that "Redshift" does not relate to stellar distances or rates of recession from Earth.

Now I'm asking, "Have we properly (experimentally) defined redshift at all?" Just what are the astronomical mechanics involved with the term 'redshift'? Does it really exist? Can we use it as a description for any kind of stellar phenomenon? And, without it, can we have any hope of accurately determining stellar distances larger than parallax allows?

All realistic information on this would be greatly appreciated.