Lemonade is a beverage created from the juice of lemons.
Benjamin Sisko offered his future wife, Jennifer, a glass of lemonade when he first met her at Gilgo Beach in 2354. She refused the offer. (DS9: "Emissary")
Benjamin Sisko's son, Jake Sisko, also enjoyed lemonade. It was available on Deep Space 9's replicators. (DS9: "Move Along Home")
Q offered William Riker a drink when he invited the Enterprise-D bridge crew to play a game for him. Moments before Riker sampled the drink, he was thinking about "an old fashioned lemonade", and thus, Q made the drink into it for him. Q also claimed that it was "an excellent thirst quencher." (TNG: "Hide and Q")
The Hot Dog Stick, a 20th century establishment in Los Angeles, specialized in selling hot dogs and fresh lemonade. (VOY: "Future's End")
While on the Caretaker's array in 2371, the crew of the USS Voyager were offered lemonade and sugar cookies. (VOY: "Caretaker")