-ιος

See also: ιός, Ίος, and ἰός

Ancient Greek

Etymology

Derived from Proto-Indo-European *-yós.

Pronunciation

(5^th BCE Attic) IPA^(key): /i.os/
(1^st CE Egyptian) IPA^(key): /i.os/
(4^th CE Koine) IPA^(key): /i.os/
(10^th CE Byzantine) IPA^(key): /i.os/
(15^th CE Constantinopolitan) IPA^(key): /i.os/

Suffix

-ῐος • (-ĭos) m (feminine -ῐ́ᾱ, neuter -ῐον); first/second declension

Suffix added to nouns or adjectives, forming adjectives: pertaining to, belonging to ("of").
1. Often added to a combination of preposition and noun (parasynthesis)
  ἀπό-γε-ιος
  apó-ge-ios
  far from earth (adj.)

Declension

First and second declension of -ῐος; -ῐᾱ; -ῐον (Attic)

Number	Singular			Dual			Plural
Case/Gender	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	-ῐος -ĭos	-ῐᾱ -ĭā	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐοι -ĭoi	-ῐαι -ĭai	-ῐᾰ -ĭă
Genitive	-ῐου -ĭou	-ῐᾱς -ĭās	-ῐου -ĭou	-ῐοιν -ĭoin	-ῐαιν -ĭain	-ῐοιν -ĭoin	-ῐων -ĭōn	-ῐων -ĭōn	-ῐων -ĭōn
Dative	-ῐῳ -ĭōi	-ῐᾳ -ĭāi	-ῐῳ -ĭōi	-ῐοιν -ĭoin	-ῐαιν -ĭain	-ῐοιν -ĭoin	-ῐοις -ĭois	-ῐαις -ĭais	-ῐοις -ĭois
Accusative	-ῐον -ĭon	-ῐᾱν -ĭān	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐους -ĭous	-ῐᾱς -ĭās	-ῐᾰ -ĭă
Vocative	-ῐε -ĭe	-ῐᾱ -ĭā	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐοι -ĭoi	-ῐαι -ĭai	-ῐᾰ -ĭă
Derived forms	Adverb			Comparative			Superlative
Derived forms	-ῐως -ĭōs			-ῐώτερος -ĭṓteros			-ῐώτᾰτος -ĭṓtătos
Notes:	This table gives Attic inflectional endings. For declension in other dialects, see Appendix:Ancient Greek dialectal declension.

First and second declension of -ῐος; -ῐη; -ῐον (Epic)

Number	Singular			Dual			Plural
Case/Gender	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	-ῐος -ĭos	-ῐη -ĭē	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐοι -ĭoi	-ῐαι -ĭai	-ῐᾰ -ĭă
Genitive	-ῐοιο -ῐοο -ῐου -ĭoio -ĭoo -ĭou	-ῐης -ĭēs	-ῐοιο -ῐοο -ῐου -ĭoio -ĭoo -ĭou	-ῐοιῐ̈ν -ĭoiĭ̈n	-ῐαιῐ̈ν -ĭaiĭ̈n	-ῐοιῐ̈ν -ĭoiĭ̈n	-ῐων -ĭōn	-ῐᾱ́ων -ῐέων -ῐῶν -ĭā́ōn -ĭéōn -ĭôn	-ῐων -ĭōn
Dative	-ῐῳ -ĭōi	-ῐῃ -ĭēi	-ῐῳ -ĭōi	-ῐοιῐ̈ν -ĭoiĭ̈n	-ῐαιῐ̈ν -ĭaiĭ̈n	-ῐοιῐ̈ν -ĭoiĭ̈n	-ῐοισῐ -ῐοισῐν -ῐοις -ĭoisĭ(n) -ĭois	-ῐῃσῐ -ῐῃσῐν -ῐῃς -ῐαις -ĭēisĭ(n) -ĭēis -ĭais	-ῐοισῐ -ῐοισῐν -ῐοις -ĭoisĭ(n) -ĭois
Accusative	-ῐον -ĭon	-ῐην -ĭēn	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐους -ĭous	-ῐᾱς -ĭās	-ῐᾰ -ĭă
Vocative	-ῐε -ĭe	-ῐη -ĭē	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐοι -ĭoi	-ῐαι -ĭai	-ῐᾰ -ĭă
Derived forms	Adverb			Comparative			Superlative
Derived forms	-ῐως -ĭōs			-ῐώτερος -ĭṓteros			-ῐώτᾰτος -ĭṓtătos
Notes:	Dialects other than Attic are not well attested. Some forms may be based on conjecture. Use with caution.

First and second declension of -ῐος; -ῐη; -ῐον (Ionic)

Number	Singular			Dual			Plural
Case/Gender	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter	Masculine	Feminine	Neuter
Nominative	-ῐος -ĭos	-ῐη -ĭē	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐοι -ĭoi	-ῐαι -ĭai	-ῐᾰ -ĭă
Genitive	-ῐου -ĭou	-ῐης -ĭēs	-ῐου -ĭou	-ῐοιν -ĭoin	-ῐαιν -ĭain	-ῐοιν -ĭoin	-ῐων -ĭōn	-ῐέων -ῐῶν -ĭéōn -ĭôn	-ῐων -ĭōn
Dative	-ῐῳ -ĭōi	-ῐῃ -ĭēi	-ῐῳ -ĭōi	-ῐοιν -ĭoin	-ῐαιν -ĭain	-ῐοιν -ĭoin	-ῐοισῐ -ῐοισῐν -ĭoisĭ(n)	-ῐῃσῐ -ῐῃσῐν -ĭēisĭ(n)	-ῐοισῐ -ῐοισῐν -ĭoisĭ(n)
Accusative	-ῐον -ĭon	-ῐην -ĭēn	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐους -ĭous	-ῐᾱς -ĭās	-ῐᾰ -ĭă
Vocative	-ῐε -ĭe	-ῐη -ĭē	-ῐον -ĭon	-ῐω -ĭō	-ῐᾱ -ĭā	-ῐω -ĭō	-ῐοι -ĭoi	-ῐαι -ĭai	-ῐᾰ -ĭă
Derived forms	Adverb			Comparative			Superlative
Derived forms	-ῐως -ĭōs			-ῐώτερος -ĭṓteros			-ῐώτᾰτος -ĭṓtătos
Notes:	Dialects other than Attic are not well attested. Some forms may be based on conjecture. Use with caution.

Derived terms

Ancient Greek terms suffixed with -ιος

-ιον (-ion, diminutives and nominalized adjectives)

Descendants

Greek: -ιος (-ios)

References

Smyth, Herbert Weir (1920), “Part III: Formation of Words”, in A Greek grammar for colleges, Cambridge: American Book Company, § 858.2

Greek

Etymology 1

From Ancient Greek -ῐος (-ĭos). Found in inherited words, and compositions of formal words.

Pronunciation

for older or formal words:

IPA^(key): /i.os/
Hyphenation: ι‧ος

Suffix

-ιος • (-ios) m (feminine -ια, neuter -ιο)

Used to form nouns and adjectives indicating origin:
‎Κύπρος (Kýpros, “Cyprus”) + ‎-ιος (-ios) → ‎Κύπριος (Kýprios, “Cypriot”) (noun, demonym)
Related term: -αίος (-aíos) for demonyms

‎θάλασσα (thálassa, “sea”) + ‎-ιος (-ios) → ‎θαλάσσιος (thalássios, “marine”) (adjective)

‎αιώνας (aiónas, “century”) + ‎-ιος (-ios) → ‎αιώνιος (aiónios, “eternal”) (adjective)

Declension

Declension of -ιος
	singular			plural
	masculine	feminine	neuter	masculine	feminine	neuter
nominative	-ιος (-ios)	-ια (-ia) -ία (-ía)	-ιο (-io)	-ιοι (-ioi)	-ιες (-ies)	-ια (-ia)
genitive	-ιου (-iou) -ίου (-íou)	-ιας (-ias) -ίας (-ías)	-ιου (-iou) -ίου (-íou)	-ιων (-ion) -ίων (-íon)	-ιων (-ion) -ίων (-íon)	-ιων (-ion) -ίων (-íon)
accusative	-ιο (-io)	-ια (-ia) -ία (-ía)	-ιο (-io)	-ιους (-ious) -ίους (-íous)	-ιες (-ies)	-ια (-ia)
vocative	-ιε (-ie)	-ια (-ia) -ία (-ía)	-ιο (-io)	-ιοι (-ioi)	-ιες (-ies)	-ια (-ia)

Derivations:
Comparative: πιο + positive forms (e.g. πιο -ιος, etc.)
Relative superlative: definite article + πιο + positive forms (e.g. ο πιο -ιος, etc.)

Etymology 2

Modern formations of derivatives from verbs or adjectives + -ιος (-ios)

Pronunciation

in one syllable:

IPA^(key): /i̯os/ with palatal variants /ʝos, ʎos, ços, ɲos/ depending on the preceding consonant
Hyphenation: ιος

Suffix

-ιος • (-ios) m (feminine -ια, neuter -ιο)

Used to form adjectives indicating property, characteristic of the prototype word:
‎σαπίζω (sapízo, “to rot”) + ‎-ιος (-ios) → ‎σάπιος (sápios, “rotten”) /ˈsapços/ (from verb)

‎καθαρός (katharós, “clean”) + ‎-ιος (-ios) → ‎καθάριος (kathários, “clear”) /kaˈθaɾʝos/ (from adjective)

Declension

Declension of -ιος
	singular			plural
	masculine	feminine	neuter	masculine	feminine	neuter
nominative	-ιος (-ios)	-ια (-ia)	-ιο (-io)	-ιοι (-ioi)	-ιες (-ies)	-ια (-ia)
genitive	-ιου (-iou)	-ιας (-ias)	-ιου (-iou)	-ιων (-ion)	-ιων (-ion)	-ιων (-ion)
accusative	-ιο (-io)	-ια (-ia)	-ιο (-io)	-ιους (-ious)	-ιες (-ies)	-ια (-ia)
vocative	-ιε (-ie)	-ια (-ia)	-ιο (-io)	-ιοι (-ioi)	-ιες (-ies)	-ια (-ia)

Derivations:
Comparative: πιο + positive forms (e.g. πιο -ιος, etc.)
Relative superlative: definite article + πιο + positive forms (e.g. ο πιο -ιος, etc.)