The verb is explained after the theonym Zeus, god of the sky and of the storm, who was responsible for rain in Greek mind (see Ζεὺς ὕει "Zeus is raining" = it rains). The theonym has a dialectal variant Δεύς, which matches exactly the verb δεύω. The etymological explanation was reversible, since this connection between Zeus and δεύω is in fact attested earlier in order to explain the theonym, which would be derived from δεύω (see Ζεύς / δεύω). Orion's etymology reverses the usual direction verb → theonym. Orion's formulation is less clear than the formulation in later sources (Etym. Magnum and Etym. Symeonis in the Parallels), in which the word is explicitly parsed as a compound of Zeus and ὕει "it rains", accounting for the intermediate step, the ghost word *διεύω: in that case Orion's formulation ὑπὸ Διὸς βρέχεσθαι, can be understood as an elliptic etymology replacing *ὕεσθαι (the passive of which is not attested) by the usual βρέχεσθαι – the full formulation would be ὑπὸ Διὸς βρέχεσθαι, ὅ ἐστιν ὕεσθαι, as in the Etym. Magnum. This implies starting from the passive δεύομαι "to be wet", not from the active δεύω – again, this is not explicit in Orion's formulation which has the active verb form as the default form for the lemma but refers to the passive meaning in the explanation