thirdconjugationio

Thirdconjugationio is a term used in Latin grammar to denote a subset of verbs within the third conjugation that form the present tense with an -io ending in the first person singular. Also called 3rd-io verbs or io-verbs, this group sits alongside the standard third conjugation (-ere) and the fourth conjugation (-ire). The distinguishing feature is the present active indicative forms such as capio, capis, capit, capimus, capitis, capiunt, with related forms in other tenses that preserve the -io pattern in the first person.

In the present tense, 3rd-io verbs typically show capio-type endings: -o, -is, -it, -imus, -itis, -iunt. The imperfect tense often involves an -ieb- stem alternation (e.g., capiebam, capiebas, capiebat, capiebamus, capiebatis, capiebant), while the future uses -iam, -ies, -iet, -iemus, -ietis, -ient (e.g., capiam, capies, capiet, capiemus, capietis, capient). Passive forms mirror this pattern (e.g., capior, caperis, capitur; capiemur, capiemini, capiuntur). Perfect tense forms typically insert -i- or -isti as in other Latin perfects.

Common examples include capio, facio, iacio, cupio, and fugio, illustrating the varied semantic range within the class. In teaching and reference works, 3rd-io verbs are treated as a distinct subgroup of the third conjugation due to their unique present-tense morphology and certain internal vowel changes.

See also: Latin verbs, Latin conjugation, third conjugation, io-verbs, 3rd-io.