Rhobs el Arsa
The Rhobs al Arsa has long been viewed as a citron hybrid, though a different cultivars have been suggested for the parent, for example, Moroccan citron as a male parent and sour orange as the female parent, citron or lemon and a mandarin., or citron and the lime. Detailed genomic analysis has shown Rhobs al Arsa to be highly similar to several cultivars of "Citrus limetta", the limetta or Persian sweet lime, and likely shared a common origin with them, arising from a cross between citron ("Citrus medica") and sour orange ("Citrus" × "aurantium"). The common lemon arose from a distinct hybridization event involving the same two species.
Limey
The term is thought to have originated in the 1850s as "lime-juicer", later shortened to "limey", and originally used as a derogatory word for sailors in the British Royal Navy. Since the beginning of the 19th century it had been the practice of the Royal Navy to add lemon juice to the sailors' daily ration of grog (watered-down rum). The vitamin C (specifically acid) in citrus fruits prevented scurvy , and helped to make these sailors some of the healthiest of the time. At that time "lemon" and "lime" were used interchangeably to refer to citrus fruits. Initially, lemon juice (from lemons imported from Europe) was used as the additive to grog on the Royal Navy ships, but was later switched to limes (grown in British colonies), not realizing that limes did not contain sufficient Vitamin C to prevent the disease.