Proto-Indo-European Roots

Root/Stem: *[email protected]ér-
Meanings:  a father
Hellenic Greek patér (a father), 
New Greek pater, pateras
Italic Latin pater (a father), Oscan patír, Umbrian patre, Marrucinian patres; 
Italian padre, Spanish padre, French pere, Occitan paire, Catalan pare, Portuguese pai
Celtic Common Celtic *atér, > 
Gaulish Ateronius (a personal name), Irish athair (father), Scottish athair, Old Irish ater, Welsh gwal-adr, Breton ual-art
Indic Sanskrit pitá, pitar- (a father)
Punjabi pyo, Hindi & Gujarati pita
Iranian Avestan pitá- (a father) 
Pashto plar, Lahnda pyu, Baluchi phith, pith, Ossetic fyd, Tadjik padar, Persian pedar
Armenian hair (a father), gen. haur
Tocharian Tocharian pácar (father)
Germanic Common Germanic *fadir, *fadhó, > 
Old High German fater, Old Icelandic fadhir, Old English faeder
German Vater, Swedish far, fader, Frisian faer, Faroese fadir, Danish fader, Norwegian far, Icelandic faoir, Dutch & Afrikaans vader
Baltic Lithuanian patinas (a male animal), Old Prussian Seme-patis (a deity; "father of earth"?, as zeme means 'ground, earth')
Notes: This word is also a representative of the r-stems nouns, which denoted kinship in the Proto-Indo-European language. Comparing with the previous Word-A-Week, this one was not preserved in too many languages. For example, no traces are found in Baltic and Slavic tongues, though their close relative Germanic has it. This can be explained by religious reasons: *[email protected]'r was one of the names of the supreme IE deity (cf. Indic dyauh pitar, Italic Juppiter, Greek Zeus patér), so Balto-Slavic people could put a taboo on pronouncing the word, choosing another one for the meaning 'father'.
In Slavic it is *otits', in Baltic *te.vas.
The root vowel here is the so-called Indo-European 'schwa', which is proved by the Indo-Iranian -i- reflection.