Sweet lemon, also called sweet limetta and sweet lime, is a low-acid citrus fruit which resembles a lime but has a sweet and mild juice. It is a hybrid of the citron and the bitter orange.
Due to its low acidity, the juice of the sweet lime oxidizes quickly on contact with air, and becomes bitter in several minutes. It should therefore be juiced immediately prior to service. It is not grown commercially in Europe or the United States.
Note that, despite sometimes being called "sweet lime", this species is not the same as the Palestinian sweet lime. In the Yucatan, where it is a key ingredient in sopa de lima, it is called simply "lima".