In fact genitive singular of this adjective; from the scholia to Homer, Iliad 2.23, where it occurs (of Atreus, father of Agamemnon). Likewise or similarly in other lexica. The first gloss suggests a relationship with dah/mwn (cf. delta 9, delta 10); the second implies a derivation from dai+/s (cf. generally delta 11, delta 17).