νᾶμα + ἐφέλκω
English translation (word)
nāma + ephelkō
English translation (etymon)
running water, stream + to drag
Etym. Magnum, Kallierges, p. 601
T. Gaisford, Etymologicum Magnum, Oxford, 1848
Νεφέλη: Παρὰ τὸ νάμα ἐφέλκειν ἐκ τῆς θαλάσσης
Nephelē "cloud" : from the fact that it drags (ephelkein) running water (nama) from the sea
Scholia in Aristophanem, Nubes 252b (scholia anonyma recentiora) (νεφέλη ἐτυμολογεῖται παρὰ τὸ νᾶμα ἐφέλκειν ἐκ τῆς ἁλός, ἢ ⸢ἀπὸ τοῦ νε στερητικοῦ μορίου καὶ τοῦ φάος, τὸ φῶς, Reg ἡ ἐστερημένη φωτός ⸢παρὰ τὸ ** Chis, ἢ παρὰ τὸ νίφω τὸ βρέχω)
Νεφέλη belongs with νέφος "cloud", not with νείφω "to snow" and is cognate with Lat. nebula "cloud", Germ. Nebel, Ved. nábhas- "cloud" (Beekes, EDG)
Persistence in Modern Greek
The word is still used in Modern Greek as a learned word to designate the 'cloud', while it also exists as a proper name. There also is the word νεφέλωμα.
This is a reformulation of Orion's etymology διὰ τὸ τὰ νάματα ἀφελεῖν ἐκ τῆς θαλάσσης (see νεφέλη / νᾶμα + ἀφαιρέω), which may be considered an improvement since it avoids the manipulation in the first member of the compound: the segmentation is ν-εφέλη, and ἑφέλκω accounts for the [e] in the first syllable. The etymology implies dropping the [k], which is not commented upon. From the semantic point of view, the etymology is similar to Orion's: the cloud takes water out of the sea to bring it to the land.