OK, I understand you have an opinion that API design should be done in a certain way (by the way, by "API" I meant like method signatures, not network API, but it could be either).
And I understand you disapprove of the word "deprecated" being used to refer to API that is discouraged, usually because it will be no longer supported/going away in the future.
But that doesn't change the history of the word. The word "deprecated" is what engineers have been using, intentionally, for several decades.
"Depreciated" is a mistaken variation. Even if you think "deprecated" has unfortunate connotations, it still doesn't make "depreciated" right. "Depreciated", as you said, means losing value over time. That is, 10% a year or something. Deprecated API does not "lose value over time".
The word "deprecated" has historically been used to mean that certain API (again, likely a method or function, I don't mean network api specifically) is now discouraged, it's use is disapproved of. Usually becuase it will be going away in the future. Arguments about whether this is the right way to do API change are entirely separate to this historical and current usage, where API change often IS done this way, and it's what the word is used for.
You can have opinions of how you'd like to people to handle API change over time, but that doesn't chagne the fact that "deprecated" is the word engineers have meant to use for decades. If you'd like to advocate for a differnet word and/or different practice you can -- but all "depreciated" has going for it is it sounds confusingly similar to "deprecated", it is not the word you are looking for.
> Not to be confused with Depreciation.
> In several fields, deprecation is the discouragement of use of some terminology, feature, design, or practice, typically because it has been superseded or is no longer considered efficient or safe, without completely removing it or prohibiting its use.
> It can also imply that a feature, design, or practice will be removed or discontinued entirely in the future
https://en.wikipedia.org/wiki/Deprecation
> In accountancy, depreciation refers to two aspects of the same concept: first, the actual decrease of fair value of an asset, such as the decrease in value of factory equipment each year as it is used and wears, and second, the allocation in accounting statements of the original cost of the assets to periods in which the assets are used (depreciation with the matching principle)
https://en.wikipedia.org/wiki/Depreciation
> In economics, depreciation is the gradual decrease in the economic value of the capital stock of a firm, nation or other entity, either through physical depreciation, obsolescence or changes in the demand for the services of the capital in question.
https://en.wikipedia.org/wiki/Depreciation_(economics)
Depreciation has nothing to do with what we're talking about, it's not the right word. Deprecation is the word that has been used for decades for API whose use is discouraged, often because it will not be supported in the future. You can argue that a new term is needed, but that's your argument not a historical usage, and there's no reason you need to limit yourselves to words that sound confusingly similar to "deprecation".