A citrus fruit (Citrus limon) with a bright yellow skin, and an ovoid shape with a bulge at the blossom end, juicy yellow flesh and a very tart, distinctive flavor.
In the US, a drink made of lemon juice, sugar and water; in the UK, a carbonated drink that doesn't necessarily contain anything closer to a lemon than a bit of citric acid. Sprite (TM) and 7-Up (TM) are examples of what would be called lemonade in many countries.
A citrus fruit that is not actually a lemon and which originated in China. Its flesh is darker and sweeter than conventional lemons almost like a cross between an orange and a lemon.