An Etymological Dictionary of the German Language/Spieß
Spieß (1.), m., ‘spear, lance, pike,’ from MidHG. spieȥ, OHG. spioȥ, m., ‘warrior's or hunter's spear’; corresponding to the equiv. Goth *spiuta- (whence OFr. espiet, ‘spear’), OIc. spjót, n. (in AS. spreót, see Spriet). Cognate terms in the non-Teut. languages are wanting. — ModHG. Spießgeselle, ‘accomplice,’ lit. ‘comrade in arms.’
Spieß (2.), m., ‘spit’ (cooking), from the equiv. MidHG. and OHG. spiȥ (gen. spiȥȥes), m.; corresponding to Du. spit, AS. spitu, E. spit. These cognates, whence the equiv. Rom. term, Ital. spito, are connected with the adj. spitz, of which AS. spitu is a subst. form. Spieß (Fr. épois) is also used in the sense of ‘dags or croches of a stag,’ a meaning not found in the earlier periods; yet ModHG. Spießer (OHG. spiȥȥo, spizzo, ‘hinnulus’), ‘young stag,’ and the borrowed Fr. term épois, ‘trochings of a stag,’ implies the existence of such a meaning. See spitz.