So the logic is that one should not use 'dish' for the rim-to-hub offset because it might be confused with a rim shape, and instead one should use 'centering' even though only the front wheel can be centered on my derailleur equipped bike and the term could even refer to the spacers I might need to use to center the rear wheel in the frame as well as to align the brakes.

I have spent the last 20 years as an editor, and if there is one thing that I have learned is that there is no such thing as the 'proper' term, and trying to enforce any term list on even a single company is like herding cats. Even when you think you have your glossary firmly nailed down, someone develops something that screws it up.

Dish is fine by me - and the trick is often not in getting the term 'right' but the description adequate that the people reading it understand what you mean even if they use other terms.