ウリ科キュウリ属の一年草で、学名は Cucumis sativus (syn. Cucumis sativus var. tuberculatus)。英名は Cucumber。
The Cucumber (Cucumis sativus) belongs to Cucurbitaceae (the Gourd family). It is an annual herb that is probably native to northern India, piedmonts of Himalaya. This herb was started to cultivate in 3 century BC. It was introduced into Japan via China before Nara Era (710-794), and used for vegetables. The Japanese name is derived from "the melon from Hu (meaning "western region")". The stem has coarse hairs, and climbs up adjacent supports by tendrils. The male flowers come in the lower part of stems, and the female ones in upper part. It is called "黄瓜" (huang gua) in Chinese.
In Korean, it's called "oi" (오이). Kimchi made with pickled cucumbers is called "oi-gim-chi" (오이김치).