|Root/Stem:||*oi-n-, *oi-k-, *oi-w-|
|Hellenic||Greek oinos 'one'|
|Italic||Latin únus 'one' >
Italian & Spanish uno, French & Romanian & Catalan un, Sardinian & Aromanian unu, Portuguese um
|Celtic||Old Irish oín, Welsh & Cornish un, Irish & Scottish aon, Breton unan|
|Indic||Mitanni Aryan aika- 'one', Sanskrit & Pali eka- 'one',
Prakrits ekko 'one'
Singhalese eka, Marathi & Nepali & Assamese & Hindi & Gujarati ek, Lahnda ikh, Punjabi yk
|Dardic & Nuristani||Kashmiri akh 'one', Dameli ek
Kati ev 'one', Kalasha ew
|Iranian||Avestan aêva- 'one', Old Persian aiva-,
Pahlavi évak, Khwarezmian 'yw, Ossetic yu, Pashto yau, Wakhi ji, Persian & Tadjik & Baluchi & Kurdish yak
|Balkan||Albanian nje", ni 'one'|
|Germanic||Common Germanic *ainaz 'one' >
Gothic ains, Old English án, Old Frisian en, Old High German ein, Old Norse einn,
German ein, Scots ane, Norwegian & Swedish en, Icelandic einn, Dutch & Afrikaans & Low Saxon een, Frisian aan
|Baltic||Old Prussian ains 'one', Lithuanian vienas, Latvian viêns|
|Slavic||Common Slavic *ed-inü 'one'|
|Notes:||The root was obviously *oi-, with different
nominal determinative suffixes which could be intechanged: Iranian and Nuristani *-w-,
Indic and Dardic *-k-, other IE groups chose *-n-.
The word *oinos in Proto-Indo-European was not a numeral, it was a typical adjective which could have feminine and neuter forms - and it remained adjective in all later Indo-European tongues. It was declined as any other substantive of o-stems.