Same entry, according to Adler, in the Ambrosian Lexicon. The headword, nominative plural of the masculine noun ἀθήρ , might be quoted from somewhere but, in an entry of this kind, does not have to have been.
Actually the stalks of cereals like wheat or barley. Mentioned from Hesiod onwards; see e.g. Xenophon, Oeconomicus 18.1 ("chaff and stalks") at web address 1 below.