Etymology tree
Proto-Indo-European *dews-?
Proto-Indo-European *dus-
Proto-Indo-European *dwóh₁
Proto-Indo-European *dwi-
Proto-Indo-European *dwóh₁
Proto-Indo-European *dwís
Latin dis-
Proto-Indo-European *lewh₃-der.
Proto-Italic *lawō
Latin lavō
Latin dīluō
Proto-Indo-European *-yós
Old Latin -ios
Latin -ius
Latin -ium
Latin dīluviumlbor.
Old Spanish diluvio
Spanish diluvio
Inherited from Old Spanish diluvio, from Latin dīluvium.