buckwheat n.

type of large forest tree noted for its smooth, silvery bark and its mast, which serves as food for animals, Middle English beche, from Old English bece "beech," earlier boece, from Proto-Germanic *bokjon (source also of Old Norse bok, Dutch beuk, Flemish boek, Old High German buohha, German Buche, Middle Dutch boeke "beech"), from PIE root *bhago- "beech tree" (cognate with Greek phegos "oak," Latin fagus "beech;" see fagus). Formerly with adjectival form beechen. Also see book (n.).

Old English hwæte "wheat," from Proto-Germanic *hwaitjaz (source also of Old Saxon hweti, Old Norse hveiti, Norwegian kveite, Old Frisian hwete, Middle Dutch, Dutch weit, Old High German weizzi, German Weizen, Gothic hvaiteis "wheat"), literally "that which is white" (in reference to the grain or the meal), from PIE *kwoid-yo-, suffixed variant form of root *kweid-, *kweit- "to shine" (see white; and compare Welsh gwenith "wheat," related to gwenn "white"). The Old World grain was introduced into New Spain in 1528. Wheaties, the cereal brand name, was patented 1925.