-eo

Borrowed from Latin -eus.

• IPA^(key): /e.o/ (stress falls on the preceding syllable)
• Hyphenation: -e‧o

-eo (adjective-forming suffix, feminine -ea, masculine plural -ei, feminine plural -ee)

1. used to form adjectives referring to the qualities of the root noun; -en, -eous, -ean
   1. used to form adjectives from materials or substances, indicating material composition:

      ‎ferro (“iron”) + ‎-eo → ‎ferreo (“made of iron”)

      ‎argento (“silver”) + ‎-eo → ‎argenteo (“made of silver”)

      ‎acqua (“water”) + ‎-eo → ‎acqueo (“made of water, watery”)

   2. used to form relational adjectives from proper nouns:

      ‎Cesare (“Caesar”) + ‎-eo → ‎cesareo (“Caesarean, of or pertaining to Julius Caesar”)

      ‎Medici + ‎-eo → ‎mediceo (“of or pertaining to the Medici family”)

• Some adjectives in -eo are borrowed directly from Latin and exhibit fossilized characteristics which are otherwise lost in the root noun:
  • corpo (“body”) → corporeo (“bodily, corporeal”) (cfr. Latin corpor-, oblique stem of corpus)
  • legno (“wood”) → ligneo (“wooden, made from wood”) (cfr. Latin lignum)
  • oro (“gold”) → aureo (“golden, made of gold”) (cfr. Latin aurum)
  • Ercole (“Hercules”) → erculeo (“Herculean, pertaining to Hercules”) (cfr. Latin Herculēs)

Borrowed from Latin -aeus, from Ancient Greek -αῖος (-aîos).

• IPA^(key): /ˈɛ.o/
• Rhymes: -ɛo
• Hyphenation: -è‧o

-eo (adjective-forming suffix, feminine -ea, masculine plural -ei, feminine plural -ee) -eo m (noun-forming suffix, plural -ei, feminine -ea)

1. used to form adjectives and nouns expressing relation to the root noun; -an, -ean
   1. forming ethnonyms from place names:

      ‎Etna + ‎-eo → ‎etneo (“of or pertaining to mount Etna; person from or inhabitant of the Etna region”)

      ‎Ragusa (city in Croatia) + ‎-eo → ‎raguseo (“of or pertaining to the city of Ragusa; person from or inhabitant of Ragusa”)

   2. forming relational adjectives from proper nouns:

      ‎Euclide (“Euclid”) + ‎-eo → ‎euclideo (“Euclidean, pertaining to Euclid”)

      ‎Augusto (“Augustus”) + ‎-eo → ‎augusteo (“Augustan, pertaining to emperor Augustus or his time”)

   3. forming relational adjectives from body parts:

      ‎carotide (“carotid”) + ‎-eo → ‎carotideo (“pertaining to a carotid”)

      ‎faringe (“pharynx”) + ‎-eo → ‎faringeo (“pharyngeal, pertaining to the pharynx”)

• (Classical Latin) IPA^(key): [e.oː]
• (modern Italianate Ecclesiastical) IPA^(key): [e.o] (stressed on the antepenult)

From Proto-Italic *-ēō, from earlier *-ējō, from verbs with Proto-Indo-European *-éh₁yeti (stative suffix) in which the first person singular always ended in *-éh₁yoh₂.

-eō (present infinitive -ēre); second conjugation, no perfect or supine stems

2. Forms stative verbs from adjectives.

   ‎clārus (“clear”) + ‎-eo → ‎clāreō (“to be clear”)

   ‎frīgus (“cold”) + ‎-eo → ‎frīgeō (“to be cold”)

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.

• -ēscō

From Proto-Italic *-eō, from causative/frequentative verbs with Proto-Indo-European *-éyeti (causative suffix) in which the first person singular ended in *-éyoh₂.

-eō (present infinitive -ēre); second conjugation, no perfect or supine stems

2. (no longer productive) Forms causative verbs from primary (third conjugation and some 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"). 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.

See the etymology of the corresponding lemma form.

-eō

1. dative/ablative masculine/neuter singular of -eus

• Sihler, Andrew L. (1995), New Comparative Grammar of Greek and Latin, Oxford, New York: Oxford University Press, →ISBN, pages 530-531
• Weiss, Michael L. (2009), Outline of the Historical and Comparative Grammar of Latin‎^[1], Ann Arbor: Beech Stave Press, →ISBN, page 404
• Olsen, Birgit Anette (2003), “Another Account of the Latin Adjectives in -idus”, in Historische Sprachforschung / Historical Linguistics‎^[2], volume 116, number 2, Vandendhoeck & Ruprecht GmbH & Co. KG, →JSTOR, page 241: “Evidently the Latin type of stative verbs in -ēre is productive”

From Latin -eus.

-eo (adjective-forming suffix, feminine -ea, masculine plural -eos, feminine plural -eas)

1. -eous; forms adjectives meaning resembling or having characteristics of the related term

• “-eo”, in Dicionário Priberam da Língua Portuguesa (in Portuguese), Lisbon: Priberam, 2008–2026

From Latin -eus.

-eo (adjective-forming suffix, feminine -ea, masculine plural -eos, feminine plural -eas)

1. -eous; forms adjectives meaning resembling or having characteristics of the related term

-eo m (noun-forming suffix, plural -eos)

1. forms nouns from verbs suffixed with -ear, meaning 'action and effect'

• “-eo”, 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