Meaning
白菜 (はくさい, Hakusai) is Nappa (napa) cabbage — a Japanese food (plants, vegetables).
What is Nappa (napa) cabbage?
Hakusai is nappa cabbage ( Brassica rapa var Pekinensis ), also called "Chinese cabbage". In Japan, it is preferred as a winter vegetable and is often cultivated and used. The word "nappa" in the name "nappa cabbage" comes from colloquial and regional Japanese, where nappa refers to the leaves of any vegetable, especially when used as food. The Japanese name for this specific variety of cabbage is hakusai , a Sino-Japanese reading of the Chinese name báicài , literally "white vegetable".