Etymology tree
Proto-Indo-European *peh₂-?
Proto-Indo-European *-tḗr
Proto-Indo-European *ph₂tḗr
Proto-Italic *patēr
Latin pater
From Proto-Italic *patēr, from Proto-Indo-European *ph₂tḗr. As a titular suffix, shares cognate roots with Old Latin Diēspiter (“Father Jove”), Latin Iuppiter (“Jupiter”).