-io

From Latin -ia in country names.

• IPA^(key): /ˈio/
• Rhymes: -io
• Syllabification: i‧o

-io

2. a place, usually a country, named after the root, whether that is a people, person, city, or river

   ‎andaluzo (“Andalusian”) + ‎-io → ‎Andaluzio (“Andalusia”)

   ‎Esperanto (“the Esperanto language”) + ‎-io → ‎Esperantio (“a notional Esperanto-speaking land”)

   ‎flandro (“Fleming”) + ‎-io → ‎Flandrio (“Flanders”)

   ‎japano (“a Japanese person”) + ‎-io → ‎Japanio (“Japan”)

   ‎Kaŭkazo (“the Caucasus Mountains”) + ‎-io → ‎Kaŭkazio (“the Caucasus (region)”)

   ‎Kolumbo (“Christopher Columbus”) + ‎-io → ‎Kolumbio (“Colombia”)

   ‎Niĝero (“the Niger River”) + ‎-io → ‎Niĝerio (“Nigeria”)

   ‎Novjorko (“New York City”) + ‎-io → ‎Novjorkio (“New York (state)”)

   ‎Romo (“Rome”) + ‎-io → ‎Romio (“the Roman Empire”)

   ‎ŝvabo (“Swabian”) + ‎-io → ‎Ŝvabio (“Swabia”)

3. a science named after its practitioner

   ‎astronomo (“astronomer”) + ‎-io → ‎astronomio (“astronomy”)

   ‎biologo (“biologist”) + ‎-io → ‎biologio (“biology”)

   ‎kirurgo (“surgeon”) + ‎-io → ‎kirurgio (“surgery (branch of medicine)”)

5. -ium; used to form the names of chemical elements

   ‎berilo (“beryl”) + ‎-io → ‎berilio (“beryllium”)

   ‎titano (“titan”) + ‎-io → ‎titanio (“titanium”)

   ‎Urano (“Uranus”) + ‎-io → ‎uranio (“uranium”)

• (place): -ujo for places named after their inhabitants: Anglujo (“England”)
• (place): lando is also sometimes used for places named after inhabitants: Svedlando = Svedio (“Sweden”)
• (science): scienco is used like a suffix with root words to form names of some sciences: vulkanoscienco = vulkanologio (“volcanology”)

From multiple sources, including extraction from words derived with -o from verb stems ending in -i, as well as from earlier and still dialectal -i(j)o, from -ja-i (for labial ai > o, compare plural forms of kala-type nouns), from -ja + -i.

-io (front vowel harmony variant -iö, linguistic notation -iO)

1. Forms nouns from verbs or verbal stems.

   ‎itää (“to sprout”) + ‎-io → ‎itiö (“spore (of e.g. mushroom, moss)”)

   ‎valita (“to choose”) + ‎-io → ‎valio (“elite, select”)

2. Forms nouns from other nouns, adjectives, numbers or their stems.

   ‎yksi (“one”) + ‎-io → ‎yksiö (“a one-room apartment”)

   ‎kolme (“three”) + ‎-io → ‎kolmio (“a triangle; a yield sign”)

   ‎neljä (“four”) + ‎-io → ‎neliö (“a square”); shorter form for a square meter

• oi

Borrowed from English -ia, French -ie, Italian -ia, Russian -ия (-ija), Spanish -ia, ultimately from Latin -ia, from Ancient Greek -ία (-ía).

-io

1. suffix denoting the country, region, domain, territory or province dependent upon the authority of a person

   ‎duko (“duke; duchess”) + ‎-io → ‎dukio (“duchy”)

   ‎episkopo (“bishop”) + ‎-io → ‎episkopio (“bishopric, diocese, episcopate”)

   ‎paroko (“parish priest, rector”) + ‎-io → ‎parokio (“parish”)

   ‎rejo (“sovereign, ruler, king, queen, monarch”) + ‎-io → ‎rejio (“kingdom”)

A common but false misconception is that countries that end with -ia in Ido, for example Albania, use this suffix when in fact it's part of the root itself. Though, -io at times can help shape country names to fit; Mexikia uses the extra i so not to be confused with Mexiko (“Mexico City”) at the same time resembling other country names.

Unknown. Perhaps from Latin -ērium.

• IPA^(key): /ˈi.o/
• Rhymes: -io
• Hyphenation: -ì‧o

-io m (noun-forming suffix, plural -ii)

2. used with verb roots to derive nouns with durative, intensive or frequentative connotation; -le

From Latin -īvus.

• IPA^(key): /ˈi.o/
• Rhymes: -io
• Hyphenation: -ì‧o

-io (adjective-forming suffix, feminine -ia, masculine plural -ii, feminine plural -ie)
-io m (noun-forming suffix, plural -ii)

2. alternative form of -ivo

From Latin -ius.

• IPA^(key): /jo/, /ˈi.o/
• Rhymes: -io
• Hyphenation: -io, -ì‧o

-io (adjective-forming suffix, feminine -ia, masculine plural -i or -ii, feminine plural -ie)

1. added to nouns and adjectives to form adjectives meaning “having the quality of”; -y

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

• IPA^(key): /jo/ (stressed on the preceding syllable)
• Hyphenation: -io

-io m (noun-forming suffix, plural -i)

2. (uncommon) used with verb roots to derive simple deverbal nouns

   Synonym: (more common) -o

   ‎sgravàre (“to relieve, to lighten”) + ‎-io → ‎sgràvio (“relief, lightening”)

Borrowed from New Latin -ium.

• IPA^(key): /jo/, /ˈi.o/
• Rhymes: -io
• Hyphenation: -io, -ì‧o

-io m (noun-forming suffix, plural -i or -ii)

2. forms the name of chemical elements; -ium

From Latin -īvit via Vulgar Latin -īut.

• IPA^(key): /jo/, /ˈi.o/
• Rhymes: -io
• Hyphenation: -io, -ì‧o

-io (non-lemma form of verb-forming suffix)

1. (Romanesco, archaic, Dantesque) used with a stem to form the third-person singular past historic of regular -ire verbs
2. (Romanesco, dated) used with a stem to form the simple past of verbs

   ...E poi annamio ar negozio a venne

   ...And then we used to go to the shop to sell

   Indove annavio?

   Where were you going?

Suffix -ō on i-stems.

-iō f (genitive -iōnis); third declension

2. Used to form abstract nouns from verbs.

The suffix -iō is added to a verb to create a third-declension feminine abstract noun.

Examples:

legiō, from legō

regiō, from regō

Third-declension noun.

• -tus

• Sihler, Andrew L. (1995), New Comparative Grammar of Greek and Latin, Oxford, New York: Oxford University Press, →ISBN

Extension of -ō (possibly by rebracketing).

-iō m (genitive -iōnis); third declension

2. forms animate nouns of various meanings, often colloquial or pejorative
   1. forms nouns designating a type of person
      1. attached to noun stems, forms nouns referring to a related profession

         Synonyms: -ārius, -ō

         ‎libellus (“booklet”) + ‎-iō → ‎libelliō m (“notary; bookdealer”)

         ‎lūdus (“performance, stage play”) + ‎-iō → ‎lūdiō m (“stage performer”)

         ‎mūlus (“mule”) + ‎-iō → ‎mūliō m (“mule-driver”)

      2. (rare) attached to verb stems, forms agent nouns

         Synonyms: -ō, -a¹, -tor

         ‎lēx (“law”) + ‎rumpō (“break”) + ‎-iō → ‎lēgirupiō m (“law-breaker”)

   2. also forms names, especially cognomina.

      Synonyms: -ō, -a¹

      ‎glaber (“smooth, hairless”) + ‎-iō → ‎Glabriō (“a Roman cognomen”)

      ‎ursus (“bear”) + ‎-iō → ‎Ursiō (“a Roman cognomen”)

   3. attached to noun stems, forms a diminutive or similar derived noun

      ‎caballus (“horse”) + ‎-iō → ‎caballiō m (“pony”)

      ‎porcellus (“little pig”) + ‎-iō → ‎porcelliō m (“woodlouse”)

4. Suffixed to noun or adjective stems, forms certain nouns designating things; often described as a kind of diminutive.

Personal appellations ending in -iō appear to have often had a derogatory or pejorative shade of meaning, which in some cases resulted in a sense near that of a diminutive, as in the case of homunciō.^[1]

Third-declension noun.

From -i-ō. Ultimately from Proto-Indo-European *-yeti.

-iō (present infinitive -iāre, perfect active -iāvī, supine -iātum); first conjugation

1. Used to form factitive verbs from adjectives.

¹At least one use of the Old Latin "sigmatic future" and "sigmatic aorist" tenses is attested, which are used by Old Latin writers; most notably Plautus and Terence. The sigmatic future is generally ascribed a future or future perfect meaning, while the sigmatic aorist expresses a possible desire ("might want to").
²The present passive infinitive in -ier is a rare poetic form which is attested.

From Proto-Italic *-jō, from Proto-Indo-European *-yéti (first person singular: *-yóh₂) after a consonant.

-iō (present infinitive -ere, perfect active -ī, supine -um); third (-iō variant) conjugation

2. Used to form some irregular third conjugation verbs.

¹At least one use of the Old Latin "sigmatic future" and "sigmatic aorist" tenses is attested, which are used by Old Latin writers; most notably Plautus and Terence. The sigmatic future is generally ascribed a future or future perfect meaning, while the sigmatic aorist expresses a possible desire ("might want to"). It is also attested as having a rare sigmatic future passive indicative form ("will have been"), which is not attested in the plural for any verb.

Ultimately from Proto-Indo-European *-yéti (denominative suffix). The question of how it came to be differentiated from third-conjugation -iō, -ere is still debated. Vine 2012 derives denominatives such as serviō from *serw-e-yé/ó- (with the thematic vowel *-e- before the suffix), proposing that unaccented Proto-Indo-European *-e- came to be assimilated in Italic to an immediately following *-y-.^[2] Alternative explanations include an Italic version of Sievers's law (that is, a prosodically conditioned development of postconsonantal *-y-* to *-iy- in certain contexts) or combination of the suffix with stems ending in *-i-. Some verbs may be derived from backformation from adjectives ending in -ītus, such as igniō, whose finite forms are attested later than ignītus (“fiery, glowing”).^[3]

-iō (present infinitive -īre, perfect active -īvī or -iī, supine -ītum); fourth conjugation

2. Used to form fourth conjugation verbs.

¹At least one use of the Old Latin "sigmatic future" and "sigmatic aorist" tenses is attested, which are used by Old Latin writers; most notably Plautus and Terence. The sigmatic future is generally ascribed a future or future perfect meaning, while the sigmatic aorist expresses a possible desire ("might want to").

(from infinitive -īre:)

From Latin -ium, from the adjectival suffix -ius.

• IPA^(key): /ˈ-io/

-io

1. (added to nouns) A suffix forming abstract nouns.

   ‎sennor (“lord, master”) + ‎-io → ‎sennorio (“dominion, jurisdiction”)

• Spanish: -ío

From Old Galician-Portuguese -io, from Latin -īvus. Doublet of -ivo.

-io (adjective-forming suffix, feminine -ia, masculine plural -ios, feminine plural -ias)

1. -ive; -y (forms adjectives from verbs, indicating a tendency or inclination)

   ‎escorregar (“to slip”) + ‎-io → ‎escorregadio (“slippery”)

   ‎arredar (“to withdraw from”) + ‎-io → ‎arredio (“withdrawn, solitary”)

-io m (noun-forming suffix, uncountable)

1. (informal) forms collectives

   ‎mulher (“woman”) + ‎-io → ‎mulherio (“a bunch of women”)

-io m (noun-forming suffix, plural -ios)

1. (chemistry) -ium (forms the names of chemical elements and isotopes)

-io

1. obsolete spelling of -iu

• “-io”, in Dicionário Aulete Digital (in Portuguese), Rio de Janeiro: Lexikon Editora Digital, 2008–2026

Borrowed from New Latin -ium, from Latin -um, based on Latin terms for metals, such as ferrum (“iron”).

• IPA^(key): /-jo/
• Syllabification: -io

-io m (noun-forming suffix, plural -ios)

1. -ium

• “-io”, in Diccionario de la lengua española [Dictionary of the Spanish Language] (in Spanish), online version 23.8.1, Royal Spanish Academy [Spanish: Real Academia Española], 15 December 2025

Variant of -o, initially after a stem that contained /j/ (for Brythonic /ɣ/ or from palatalization after a diphthong), later extended to other verb stems.

• IPA^(key): /jɔ/

-io

1. Forms verbnouns from verbs and other parts of speech.

• -o (Forms verbnouns from verb stems ending in i̯)