I see on the Wikipedia article it seems to say that lemonade in the USA is flat, not fizzy? I think this is where I confused your question and we got our wires crossed. Anything that ended “ade” in the UK is a fizzy drink, like a pop/soda. Lemonade, cherryade, orangeade etc. Schweppes, Barr’s etc make lemonade like that, clear, sweet fizzy and just lemon flavour.
I can’t think of a drink that’s fresh lemon juice as described on wiki over here. There is squash, or cordial, diluted juice with water. But lemon wasn’t common or popular to the best of my knowledge. I’ll look when I’m in asda the morn now though, just to see for curiosity.