SPRUCE, i.e. spruce-fir, a coniferous tree belonging to the genus Picea, of which there are several species, such as the Norway spruce, Picea excelsa; the black spruce, Picea nigra, etc. (see FIR)'. The name has a curious origin, which explains also the particular meaning of the adjective " spruce," neatly dressed, smart in appearance, fine. From a number of early quotations given by Skeat (Etym.Dict.) it is clear that " spruce " a variant of "pruce," simply stood for Prussian; the form "spruce," rather than " pruce," being established partly by the German Sprossen, sprouts or young shoots (seen in Sprossen-bier, spruce beer, made of the sprouts of this fir).
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)