'citrusy' originates from English, specifically the word 'citrus' with the adjectival suffix '-y', where 'citrus' meant 'citron or citrus fruit'.

'citrus' entered English from Latin 'citrus', which in turn comes from Greek 'kitron' (kítron) referring to the citron; the adjective 'citrusy' was formed later in English by adding '-y' to 'citrus'.

Initially, 'citrus' referred specifically to the citron tree/fruit; over time it came to denote the broader group of citrus fruits and their characteristic flavors/odors, and 'citrusy' developed to describe qualities reminiscent of these fruits.