δῶ ‘house’ and the Nom. Sg. of -ον-stems

While word-final ∗–n was lost after ∗–ō in Proto–Indo–European (e.g. Ved. rā́ jā ‘king’ ∗di̯ émm > ∗di̯ ḗm, cf. Ζῆν(α) ‘Zeus’) is operated, and the developments of ∗dh(e)g̑ hom–m > ∗dh(e)g̑ hōm (cf. χθών ‘earth’) and ∗ ̑ghéi̯ –om–m > ∗ ̑ghéi̯ ōm (cf. χιών ‘snow’) take place; (3) in Greek, final –ν of nom. sg. of –ον–stem noun is restored after the analogy of other cases (e.g. ∗τεκτω >> τέκτων, cf. e.g. τέκτονος [gen.]) and accusative singulars of χθών and χιών end in –όνα to distinguish between nom. and acc. forms; in contrast, ∗–n of a neuter noun ∗dṓ ‘house’ is not restored with analogy, because the nom. sg. and the acc. sg. are both ∗ dṓ , and because due to its irregular declension derived δῶμα ‘house’ is already used frequently; and (4) ∗dṓ is petrified in epic poetry and bears a circumflex accent δῶ with analogy of δῶμα