LATIN DICTIONARYLexicon Latīnum
interjection

iō1

iō
Classical[ˈi.oː]Ecclesiastical[ˈiː.o]

Meaning

  1. an exclamation of joy: hurray, hurrah, yay
  2. an exclamation of pain: oh, ah, alas
    illa quidem clāmābat ‘iō, cārissima māter, auferor!’ Indeed, she was crying out, “Oh! mother dearest – I am being taken away!”(See Persephone. The full context implies a cry of anguish as well as a plea for help from Persephone's mother, Ceres. The alternative ‘‘Help!’’ calls for an imperative such as ‘‘ferte auxilium!’’.)8 CE, Ovidius, Fasti 4.447–448
  3. an exclamation for getting attention: hey, oi, look, quick

ĭō, interj. ἰώ, expressing joy,
I. ho! huzza! hurra! io hymen hymenaee, io hymen, Plaut. Cas. 4, 3, 3; id. Ps. 2, 4, 11: miles, io, magna voce, triumphe, canet, Tib. 2, 5, 121 (118): io triumphe! Hor. C. 4, 2, 49: io, io, liber ad te venio, Plin. Ep. 3, 9.—
II. Expressing pain, oh! ah! io! enicas me miserum, Plaut. Truc. 1, 2, 21: uror, io, remove saeva puella faces! Tib. 2, 4, 6.—
III. Used in a sudden or vehement call, holla! look! quick! io! matres, audite, Verg. A. 7, 400: io! comites, his retia tendite silvis, Ov. M. 4, 513; id. A. A. 3, 742.

Origins

Echoic; compare Ancient Greek ἰώ (iṓ), or English yo.

proper noun · femininefourth declension
Īō2
Īō f sg (genitive Īūs)
Classical[ˈiː.oː]Ecclesiastical[ˈiː.o]

Meaning

  1. GreekIo, daughter of Inachus.
    Et modo se Europen fieri, modo postulat Io,Now she would be Europa; now she would be Io; the one because she was a heifer, the other because a bull bore her on his back.Publius Ovidius Naso, Ars amandi / Ars amatoria, liber I. In: Publius Ovidius Naso: Liebeskunst. Lateinisch-deutsch, 1980, p. 28 – translation from The Love Books of Ovid, p. 121
    Publius Ovidius Naso, Amores, liber II. In: Ovid Heroides and Amores with an English translation by Grant Showerman, 1914, p. 386f. dum nimium servat custos Iunonius Ion, ante suos annos occidit; ilia dea est! Juno's watchman, guarding Io too intently, falls before his time; she–becomes a goddess!

Declension

declension
formsingularplural
nominativeĪō
Īōn		—
genitiveĪūs
Īōnis		—
dativeĪō
Īōnī		—
accusativeĪō
Īōnem		—
ablativeĪō
Īōne		—
vocativeĪō
Īōn		—

Īō, Iūs, and Īōn, Iōnis, f., = Ἰώ,
I. a daughter of Inachus, king of Argos, beloved by Jupiter, and changed, through fear of Juno, into a cow; afterwards worshipped as an Egyptian deity, under the name of Isis. —Form Io, Ov. H. 14, 85; Prop. 2, 28 (3, 24), 17; Ov. M. 1, 588 sq.; Val. Fl. 4, 351 sq.; Hyg. Fab. 145.—Gen. Ius, Nemes. Cyn. 31.—Acc. Io, Ov. M. 1, 588; Amm. 2, 19, 29.—Abl. Io, Prop. 2, 13, 19.—Form Ion; dat. Ioni, Plaut. Aul. 3, 6, 20.—Acc. Ionem, Serv. Verg. A. 3, 153.

Origins

From Ancient Greek Ἰώ (Iṓ).

In the Academy Smith's classical dictionaries

Biography & mythologyIoIo. 2. The wanderings of Io. --The idea of Io having wandered about after her metamorphosis appears to have been as ancient as the mythus respecting h…

Quick answers

What does iō mean in Latin?
iō, a interjection, means “an exclamation of joy: hurray, hurrah, yay; an exclamation of pain: oh, ah, alas; an exclamation for getting attention: hey, oi, look, quick”.
How do you pronounce iō?
In classical Latin, [ˈi.oː]; in ecclesiastical (church) Latin, [ˈiː.o].