Vassati¹

to rain (intrs.), fig to shower, pour(down) Vin.i.32 (mahāmegho vassi) SN.iii.141 (deve vassante); SN.v.396 (id.); Snp.30 (devassa vassato, gen. sg. ppr.); Pv-a.6, Pv-a.139, Pv-a.287; Mhvs.21, Mhvs.33; Dhp-a.ii.83 (vassatu, imper.; vassi, aor.); Dhp-a.ii.265 (devo vassanto nom. sg.)
■ Cp. kālena kālaṃ devo vṛṣyate Divy.71
caus 2 vassāpeti to cause to rain Ja.v.201 (Sakko devaṃ v. let the sky shed rain)
pp vaṭṭa vaṭṭha, vuṭṭha. Another pp. of the Caus. *vasseti is vassita.

vṛṣ, varṣati, vṛṣate; Idg. *ṷers to wet, cp. Vedic vṛṣa bull, varṣa rain, vṛṣabha (P. usabha), Av. varšna virile, Lat. verres boar; Gr. α ̓́ρρην virile, ε ̓́ρση dew with which root is connected *eres to flow: Sk. arṣati ṛṣabha bull, Lat. ros dew = Sk. rasa essence etc. Dhtm.471 gives “secana” as defⁿ

Vassati²

to utter a cry (of animals), to bellow, bark, to bleat, to crow etc. SN.ii.230; Ja.i.436 (of a cock); Ja.ii.37 Ja.ii.153, Ja.ii.307; Ja.iii.127; Ja.vi.497 (ppr. vassamāna = vāsamāna C.)
pp vassita².

vāś to bellow, Vedic vāśyate; Dhtm.471: “saddane”