līmah

Līmah (ليمة) in Arabic meant a citrus fruit, borrowed from Persian līmū, which itself came from a South or Southeast Asian source — the fruit originated in the Malay Archipelago or southern India. The Arabic word covered citrus generally, not just the small green fruit English now calls a lime. When the word entered Spanish as lima and French as lime in the medieval period, it named the sweet lime, not the sour one. The narrowing to the small, sour, green fruit happened in English.

The British Navy's connection to limes began in 1747, when James Lind, a naval surgeon, proved that citrus juice prevented scurvy. By 1795, the Admiralty required daily lime or lemon juice rations for all sailors. British sailors became known as 'limeys' — a term Americans used derisively from the nineteenth century onward. The nickname stuck. The fruit that saved the Navy's fighting force became its identity.

There was a problem, however: limes have less vitamin C than lemons. The Navy switched from lemons to limes in the mid-nineteenth century because limes were cheaper and more available from Caribbean colonies. Scurvy rates crept back up. The substitution was a cost-cutting measure that weakened the very protection the policy was designed to provide. The word lime and the word lemon were not interchangeable, and neither were the fruits.

Lime entered English from French in the seventeenth century. The lime in 'limestone' and 'lime mortar' is a different word entirely — from Old English līm (cement, sticky substance), with no connection to the citrus. English happens to have two unrelated words that are both spelled lime: one is a fruit from Arabic, the other is a mineral from Germanic. They share nothing but letters.