Lime is now very much part of our culinary life in Western Europe, but all too often it is used carelessly as a substitute for lemon, often with dire consequences. Used correctly, lime is an invaluable and irreplaceable product in the kitchen.

Lime tree
Lime leaves and flower
Limes ripening on tree
Lime tree
Lime leaves and flower
Limes ripening on tree

Species:Citrus aurantifolia.
Probably South-East Asia.
In contrast to the more subtropical lemon, lime requires a tropical climate. It probably stems from South-East Asia where many related species grow wild. Today, many different lime varieties are known and cultivated. Small-fruited, highly aromatic cultivars grown on Key West in the US are called "key limes" and limes cultivated in tropical Asia have similar fruits. Large-fruited cultivars are generally regarded as inferior.
Used Part:
Juice and fruit skin (pericarp). The fruits are almost always picked when unripe (green) and are usually consumed before they reach the ripe state (yellow).
Rutaceae (citrus family).
Limes have an odour similar to that of lemon but more fresh. The juice is as sour as lemon juice but more aromatic.
For derivation of the botanical genus name citrus, see lemon. The species name aurantifolius "orange-leaved" is derived from an outdated botanical name of orange, citrus aurantium.
The English term "lime" has many relatives in other European languages, e.g. German limette, Dutch limoen, Polish limetka, Italian lima, French limon, Greek and Hebrew laim and Japanese raimu. These are similar to the commonly found names for the lemon, e.g. English "lemon", Portuguese limão, Italian limone, Croatian limun, Bulgarian and Hebrew limon and Japanese remon. All these names originate from Arabic limun and Persian limou "lemon", which can be used for either fruit. The two fruits have a long history of mutual confusion.
Limes, as tropical fruits, have little tradition in Europe and hence name is often formed from the name of lemon by adding an adjective reflecting some typical property of lime, e.g. Spanish limón agria "sour lemon", Turkish tatlı limon "sweet lemon" and Romanian lămâi mexican "Mexican lemon2.
The English name "lime" must not be confused with its homonym, meaning a building material of calcium oxide. The latter is related to loam or slime and derives from an Indo-European root lei- with general meaning "smear" or "glue" (cf. German lehm "clay").
The English name "lime" (or Old English linden) has another meaning, referring to the trees of genus tilia or malvaceae, for example in the phrase from the epic poem Beowulf lind wið lige "the linden (wooden shield) against the fire of the dragon". That name linden has cognates in various languages (Norwegian lind, Czech lípa and Russian lipa) and is probably derived from the Indo-European root lent "flexible", referring to the soft wood of linden trees.
Limes are small citrus fruits which are usually harvested while green. They are a common food ingredient in parts of Asia and Central America. Most often used is the fruit juice, which imparts a sour and refreshing fragrance to cold and warm dishes and drinks. Lime juice resembles lemon juice in its acidity but is much more aromatic. If lime juice is substituted by lemon juice the result tends to lack savour and be disappointing. Culinary usage of lime is almost restricted to tropical countries.
In tropical Asia, lime juice is often used as a basis for fresh-tasting sauces. Vietnamese nuoc cham is an everyday sauce made from lime juice, sugar, the fish sauce nuoc mam and a dash of garlic and fresh chilli. Nuoc cham is served as a table condiment to almost every Southern Vietnamese food.
Depending on the mood of the cook, the flavour of that sauce will be dominated either by the salty fish sauce or by the acidic lime juice, with the other flavours remaining in the background. A similar, less pungent sauce is Cambodian tik marij made from ground pepper, salt and lime juice, but without fish flavourings.
In South-East Asia, the zest of local citrus species is also used for cooking and limes work well in such recipes. Thais and Malays sometimes add whole fruits of kaffir lime to their curries and in the Philippines the local fruit kalamansi (citrofortunella mitis) is cultivated for both juice and peel. Indonesian cuisine makes use of lime, whose name jeruk may equally apply to lemon or orange.
A unique culinary product depending completely on lime juice is ceviche, a common method of preparing very fresh fish in Polynesia and Latin America. Raw fish is marinated with lime juice overnight and then seasoned with fresh chilli and coriander leaves, with onion and tomatoes added. The recipe appears to be of Polynesian origin, but is today often found along the Pacific coast from Mexico to Peru and on the Caribbean islands and has found its way into fine dining restaurants across the world.
The method of preparing ceviche depends on the fact that proteins denaturise in an acidic medium as they do at high temperatures, so the fish is 'cooked' by the cold but sour lime juice. Ceviche cannot be compared to the Japanese versions of raw fish (sashimi) in which the protein is not denaturised at all.
In the Gulf countries, ripe limes are boiled in salt water and then sun-dried until their interior turns dark and is known as black lime. The resulting spice is called loomi in the countries of the Arab peninsula and in Iran is known as Omani after the main production country, Oman. Black limes are often used to impart a distinct citrus odour and a sour tang to legumes and meat dishes. They are either crushed or pierced with a skewer before use and then added to slow-simmering foods. Examples are machboos (an aromatic rice dish prepared in the Gulf States) and the Iranian herb sauce ghorm.
In Iran and North India, powdered loomi is also used to flavour the long-grain Indian basmati rice. Lime juice (or sometimes lemon juice) is also contained in the Yemeni spice paste zhoug.