Meaning
ラッキョウ (らっきょう, Rakkyo) is Chinese onion — a Japanese food (plants, spices garnish dips sauces).
What is Chinese onion?
Rakkyō ( Allium chinense ) is closely related to the onion, shallot, leek, chive, and garlic. Owing to its very mild and "fresh" taste, rakkyō is often pickled and served as a side dish in Japan, to balance the stronger flavor of some other component in a meal. For example, it is eaten with Japanese curry as a garnish.