This entry is from the Lexicon Ambrosianum (Ambrosianus B 12 sup. 45 and Laurentianus 59.16 fol. 187r) and its origin is in a scholion to Homer, Iliad 4.1 (describing a meeting of the gods).
The headword verb is an epic form of the imperfect of a)gora/omai which occurs not only in Homer but also in several post-classical epic poets (Apollonius of Rhodes, Quintus, Nonnus) who take Homer as their model. This same form is to be found also in Herodotus.
The precise meaning of the verb in the Homeric passage carries a dual sense: to meet in assembly, and to speak there. On this see e.g. Porphyrius, Questionum Homericarum ad Iliadem pertinentium reliquiae 4.1: 'Aristarchus considered h)goro/wnto as meaning they gathered together, but is better to say they discussed… If indeed [Homer] meant they gathered together, would have written oi( de\ qeoi\ pa\r *zhni\ kaqh/menoi h)gere/qento; and the gods, seated near Zeus, h)gere/qento [gathered together]' (as in Iliad 11.770, 24.790 and elsewhere).