Limey

Limey is US slang for a British person since the late 19th century and is an abbreviation of lime-juicer which dates from the 1850s. Originally, the term referred specifically to British sailors because of their enforced habit (since 1795) of drinking lime juice to prevent scurvy. Scurvy had been a debilitating disease aboard ships for centuries before it was discovered that it was caused by a deficiency of Vitamin C. By the time the Americans, and indeed sailors everywhere, followed suit and adopted the lime juice habit, this name for the British was already well established. Thus, for Americans, Brits have remained limeys ever since.