Translation guide
The edible corm of the plant Eleocharis dulcis, used as a vegetable in Asian cooking. Known for its crisp texture and mild sweetness.
くわい
Chinese water chestnut
Most common term, though it can also refer to a different species in Japan.
Referring to the edible corm itself, typically in cooking or eating contexts.
The most common Japanese word for the Chinese water chestnut. Note that in Japan, a different species (Sagittaria trifolia) is often called くわい, but in international contexts, this is the standard translation.
この炒め物にはくわいが入っています。
This stir-fry has Chinese water chestnuts in it.
Literally 'large black water chestnut', this is the specific Japanese name for Eleocharis dulcis. Used in botanical or precise contexts.
オオクログワイは中国料理でよく使われる。
Chinese water chestnuts are often used in Chinese cuisine.
Literally 'Chinese water chestnut', this term explicitly distinguishes it from the Japanese variety.
中国くわいの缶詰を買いました。
I bought a can of Chinese water chestnuts.
In English, 'water chestnut' can refer to the unrelated aquatic plant Trapa natans (ヒシ in Japanese). Chinese water chestnut is a different species. Be careful not to confuse them.