The concept of 'gift' is inherent in the meaning of donation and has been understood that way for centuries: https://www.etymonline.com/word/donate#etymonline_v_31787

Do you similarly hold that Nix v. Hedden decided whether we can refer to a tomatos as fruit or vegetable? Words can have different specific meaning in different specific contexts.

Even within the legal context of one country, you may for example be "a resident" by immigration law while "not a resident" by tax law, or vice-versa.

https://en.wikipedia.org/wiki/Nix_v._Hedden

And why are you asserting the technical tax framework is relevant here?