The citron is a fragrant citrus fruit (Citrus aurantifolia), botanically classified as Citrus medica by both the Swingle and Tanaka systems.
The designation medica given it by Linnaeus is apparently derived from its ancient name "Median or Persian apple" that was reported by Theophrastus, who believed it to be native to Persia or the land of the Medes; there is no relation to medicinal uses of the fruit.