An Etymological Dictionary of the German Language/Annotated/Tanne
Tanne, feminine, ‘fir tree,’ from the equivalent Middle High German tanne, feminine, Old High German tanna, signifies ‘fir tree, oak,’ hence the primary idea of the word is usually ‘forest tree’ (see Eiche, Buche). This is supported by Modern High German Tann, masculine, from Middle High German tan (nn), masculine and neuter, ‘forest’' (Old High German tan-ęsil, ‘wild ass’), which seems to be based on a collective signification of Tanne. The early history of the High German cognates (to which Old Dutch dęnnia, Dutch den, ‘fir tree,’ is allied) is uncertain. Its connection with Greek θάμνος, ‘thicket,’ is dubious.