fagusn.

fagus (n.)botanical genus of beech trees, from Latin fagus "beech," from PIE root *bhagos "beech tree" (cognates: Greek phegos "oak," Latin fagus "beech," Russian buzina "elder," Old English bece, Old Norse bok, German Buche "beech"), perhaps with a ground sense of "edible" (and connected with the root of Greek phagein "to eat;" see -phagous). Beech mast was an ancient food source for agricultural animals across a wide stretch of Europe. The restriction to western IE languages and the reference to different trees have suggested to some scholars that this word was not PIE, but a later loanword. In the Balkans, from which the beech started to spread after 6000 BC, the [Greek] word means \\'oak,\\' not \\'beech.\\' Yet \\'oak\\' and \\'beech\\' are both \\'fruit-bearing trees,\\' so that a semantic shift from \\'oak\\' to \\'beech\\' appears quite conceivable. The word itself may then have been PIE after all. [de Vaan]