No citrus fruit is native to Europe — they arrived in waves from Southeast Asia, and Latin citrus may originally have named a luxury African wood, not a fruit at all.
A genus of flowering trees and shrubs producing acidic fruits with leathery rinds, including oranges, lemons, limes, and grapefruit. Also the fruit of these plants.
From Latin citrus (citron tree, African cypress), possibly from Greek kedros (cedar, juniper) or from an unknown Mediterranean or Asian source, as citrus fruits originated in Southeast Asia Key roots: citrus (Latin: "citron tree (possibly related to cedar/aromatic trees)").
All citrus fruits originated in Southeast Asia and did not exist in Europe until trade brought them westward. The citron arrived first (possibly by Alexander the Great's time), followed by the sour orange and lemon (medieval Arab trade), and the sweet orange (Portuguese traders, c. 1500). Latin citrus may originally have referred to an aromatic wood — possibly the North African citrus wood (Tetraclinis articulata), used for luxury furniture — before being transferred to the citron fruit. The word "citric" (as in citric acid) and "citadel