Sour Citrus is a term used to describe citrus fruits such as lemons that have a sharp, acidic taste. The most common example of a sour citrus fruit is the LEMON, which has five letters in its name. Lemons are widely used in cooking and baking, as well as for their juice, which is often used to add flavor to drinks and dishes. Lemons are also known for their health benefits, such as providing Vitamin C and aiding digestion.