Small three-sided seeds of a plant unrelated to wheat. The darker flour is pressed into noodles in the north and made into flat cakes in the southwest; Tartary buckwheat is brewed as a slightly bitter tea.
荞 contains 艹 (grass radical) + 乔 (tall, phonetic). 麦 means wheat or grain. So 荞麦 is literally 'the plant grain' - a grass-family grain like wheat but distinct.