citrus fruits 
Somewhat acidic fruits with a high vitamin C content comprising numerous sections and covered with a rind that has an external layer called zest.
Intensely fragrant and used like the lemon; it is an essential ingredient in ceviche, a raw marinated fish dish.
Because its greenish flesh is inedible, it is primarily used for the zest and essential oil derived from its rind, especially in Earl Grey tea.
Small citrus fruit, .75 to 2 in long with a sweet tender rind that can be eaten unpeeled; its flavor is enhanced through light steeping.
Highly acidic, it is especially used to flavor various recipes and enhance the flavor of certain foods; it is the main ingredient in lemonade.
Similar to a small, slightly flattened orange, it is less acidic than most citrus fruits and is often eaten as is; it peels easily.