Reconstruction:Proto-Indo-European/-os

See also: Reconstruction:Proto-Indo-European/-ós, and Reconstruction:Proto-Indo-European/-ōs

This Proto-Indo-European entry contains reconstructed terms and roots. As such, the term(s) in this entry are not directly attested, but are hypothesized to have existed based on comparative evidence.

Proto-Indo-European

Suffix

*(é)-os n

Creates action nouns or result nouns from verbs.

Inflection

Athematic, acrostatic
	singular
nominative	*(é)-os
genitive	*(é)-esos
	singular	dual	plural
nominative	*(é)-os	*(é)-esih₁	*(é)-ōs
vocative	*(é)-os	*(é)-esih₁	*(é)-ōs
accusative	*(é)-os	*(é)-esih₁	*(é)-ōs
genitive	*(é)-esos	*?	*(é)-esoHom
ablative	*(é)-esos	*?	(é)-esmos, (é)-esbʰos
dative	*(é)-esey	*?	(é)-esmos, (é)-esbʰos
locative	(é)-es, (é)-esi	*?	*(é)-esu
instrumental	*(é)-esh₁	*?	(é)-esmis, (é)-esbʰis

Derived terms

Proto-Indo-European terms suffixed with *-os (athematic)

*(é)-ēs (< **(é)-es-s)
*(é)-ōs (< **(é)-os-s)

Descendants

Proto-Celtic: *-os (s-stem nouns)
Proto-Germanic: *-az (z-stem nouns)
Proto-Hellenic: *-os (s-stem nouns)
- Ancient Greek: -ος (-os)
Proto-Hellenic: *-ehen (< alternative locative form *-esen)
- Ancient Greek: -ειν (-ein)
Proto-Balto-Slavic: *-a
- Latvian: -a, -s
- Lithuanian: -a, -as
- Proto-Slavic: *-o (s-stem nouns)
Proto-Indo-Iranian: *-as
Proto-Italic: *-os
- Old Latin: -os
  - Latin: -us
Proto-Italic: *-ezi (< locative ending *-esi)
- Latin: -ere, -erī
Proto-Albanian: *-ʉh
- Albanian: -ë
- Albanian: -ëri
Illyrian: *-urio

Suffix

*(ó)-os m

Creates nouns from verb stems denoting the performance or result of that verb.

Inflection

Thematic
	singular
nominative	*(ó)-os
genitive	*(ó)-osyo
	singular	dual	plural
nominative	*(ó)-os	*(ó)-oh₁	*(ó)-oes
vocative	*(ó)-e	*(ó)-oh₁	*(ó)-oes
accusative	*(ó)-om	*(ó)-oh₁	*(ó)-oms
genitive	*(ó)-osyo	*?	*(ó)-oHom
ablative	*(ó)-ead	*?	(ó)-omos, (ó)-obʰos
dative	*(ó)-oey	*?	(ó)-omos, (ó)-obʰos
locative	(ó)-ey, (ó)-oy	*?	*(ó)-oysu
instrumental	*(ó)-oh₁	*?	*(ó)-ōys

Reconstruction notes

This type of thematic action noun, with stress on the first o-grade vowel, is known as the τόμος (tómos)-type nouns in the literature.

Derived terms

Proto-Indo-European terms suffixed with *-os (thematic)

Related terms

Descendants

Anatolian:
- Hittite: a-stem nouns
Proto-Balto-Slavic: o-stem nouns
Proto-Celtic: *-os (causative/iterative verbal noun suffix)
Proto-Germanic: a-stem nouns
Proto-Hellenic: o-stem nouns
- Ancient Greek: τόμος-type nouns
Proto-Indo-Iranian: a-stem nouns
Proto-Italic: o-stem nouns