noun
Refers specifically to the black variety of soybean, often used in Japanese cuisine for dishes like kuromame.
See also: 黒豆
黒大豆はおせち料理の黒豆に使われます。
Black soybeans are used for the kuromame in New Year's dishes.
黒豆 often refers to the cooked dish or the beans in a culinary context, while 黒大豆 is the more formal term for the raw legume.
Compound of 黒 (black) and 大豆 (soybean).