Meaning

noun any of numerous fruits of the genus Citrus having thick rind and juicy pulp; grown in warm regions

noun any of numerous tropical usually thorny evergreen trees of the genus Citrus having leathery evergreen leaves and widely cultivated for their juicy edible fruits having leathery aromatic rinds

originFrom Latin citrus (“a citron tree, thuja”), probably via Etruscan from Ancient Greek κέδρος (kédros); compare Middle English citurtre, cytyr tre. Thus a possible doublet of cedar.

Etymology from Wiktionary, CC BY-SA 3.0