[1] Likewise or similarly in other lexica; references at Photius alpha2197 Theodoridis (dative case, quoted from Homer, Iliad 21.21). The headword originally denoted a sword, especially one on a hanger, but later, and certainly by the Suda's time, could refer to any weapon; see LSJ s.v. The noun shows the o-grade (or perhaps an Aeolic zero-grade) of a root which appears in the e-grade in the verb a)ei/rw: see Chantraine s.v. The alpha can be either long (a)=or with a circumflex accent) or short (a)/or with an acute accent) in epic.
[2] These are the genitive and dative of the neuter a)=or, so the accusative would also be a)=or.
[3] Greek Anthology 9.397.1-2 (Palladas): cf. delta 490.