After the initial glossing, the issue addressed here is to explain why some verbs beginning with alpha do not have eta when they are augmented in the imperfect.
[1] The primary headword -- a single word in the Greek -- occurs in Homer, Iliad 10.493 (web address 1), and these glosses are from the scholia there. The present indicative is unattested outside lexicography (though its participle occurs in later poetry: see LSJ s.v. at web address 2).
[2] cf. alpha 649.
[3] a)/i+on occurs as first person singular imperfect of a)i/w "breathe" (a variant of a)/hmi) in Homer, Iliad 15.252.
[4] a)/i+e, a)/i+on occur as imperfect of a)i/w "hear" in epic and lyric poetry.