What fruit comes in the Key and Kaffir varieties?

A lime (from French lime, from Arabic līma, from Persian līmū, "lemon") is a hybrid citrus fruit, which is typically round, lime green, 3–6 centimetres (1.2–2.4 in) in diameter, and containing acidic juice vesicles. There are several species of citrus trees whose fruits are called limes, including the Key lime (Citrus aurantifolia), Persian lime, kaffir lime, and desert lime. Limes are an excellent source of vitamin C, and are often used to accent the flavours of foods and beverages. They are grown year-round. Plants with fruit called "limes" have diverse genetic origins; limes do not form a monophyletic group.

Although the precise origin is uncertain, wild limes are believed to have first grown in Indonesia or Southeast Asia, and then were transported to the Mediterranean region and northern Africa around 1000 CE.

To prevent scurvy during the 19th century, British sailors were issued a daily allowance of citrus, such as lemon, and later switched to lime. The use of citrus was initially a closely guarded military secret, as scurvy was a common scourge of various national navies, and the ability to remain at sea for lengthy periods without contracting the disorder was a huge benefit for the military. The British sailor thus acquired the nickname, "Limey" because of their usage of limes.