Vested Id wrote:

Commander Tansin A. Darcos wrote:

I found this answer unsatisfactory, because lemonade is a soft drink

No it isn't

and so is orange soda, neither is carbonated.

...

So I rewrote it to read:
Water, processed by the addition of non-alcoholic flavor(s), often enhanced by the addition of sweeteners and carbonation. (In this sense, juice, milk, tea and coffee are not soft drinks, while lemonade, tonic water, and orange soda, while not carbonated, are.)

It's defined against hard drinks. Iced tea and lemonade are served alongside soft drinks, they're not soft drinks. I admit you've soft-pilled me a bit here, but that's the clear and present understanding.