io

¹ American  

[ee-oh] / ˈi oʊ /

Or 'io

noun

plural

ios

1. a small, solitary hawk, Buteo solitarius, having two plumage phases and breeding only on the Island of Hawaii, where it is a rare species and the only indigenous bird of prey: classified as near threatened.

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Io ² American  

[ahy-oh, ee-oh] / ˈaɪ oʊ, ˈi oʊ /

noun

1. Classical Mythology. a woman who, being loved by Zeus, was transformed into a white heifer and was, at the wish of Hera, first guarded by Argus and later pursued through the world by a gadfly until she reached Egypt, where she resumed her true shape: identified by the Egyptians with Isis.

2. Astronomy. a large volcanically active moon of the planet Jupiter.

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Io ³ American  

[ahy-oh, ee-oh] / ˈaɪ oʊ, ˈi oʊ /

noun

plural

Ios

1. Io moth.

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Io ⁴ American  

Symbol, Chemistry.

1. ionium.

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Io. ⁵ American  

abbreviation

1. Iowa.

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I/O ⁶ American  

1. inboard-outboard.

2. Computers. input/output.

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I.O. ⁷ American  

Or IO,

abbreviation

1. indirect object.

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Io ¹ British  

/ ˈaɪəʊ /

noun

1. the innermost of the four Galilean satellites of Jupiter, displaying intense volcanic activity. Diameter: 3640 km; orbital radius: 422 000 km

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io ² British  

abbreviation

1. British Indian Ocean Territory

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Io ³ British  

/ ˈaɪəʊ /

noun

1. Greek myth a maiden loved by Zeus and turned into a white heifer by either Zeus or Hera

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I/O ⁴ British  

abbreviation

1. input/output

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Io ⁵ British  

symbol

1. ionium

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Io Scientific  

/ ī′ō,ē′ō /

1. One of the four brightest satellites of Jupiter and the fifth in distance from the planet. It was first sighted by Galileo.

2. See Note at moon

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Etymology

Origin of io

From Hawaiian ʿio

Example Sentences

On Wednesday, OpenAI said it’s buying io, an AI devices startup that Ive founded a year ago, for nearly $6.5 billion in an all-stock deal, the largest acquisition in OpenAI’s history.

From Los Angeles Times • May 21, 2025

The idea for io, which Sir Jony founded last year, grew out of several years of quiet collaboration between the two companies, according to the announcement.

From BBC • May 21, 2025

SALZBURG, Austria — “Chi son io, tu non saprai,” the stage director Romeo Castellucci said during a recent interview in the lobby of the Salzburg Festival’s main theater.

From New York Times • Jul. 22, 2021

On the day of the Science story, the Sci-Hub twitter account reported that the io domain had been blocked in many places, but it popped back up on sci-hub.bz and sci-hub.cc.

From Nature • May 1, 2016

Wasn't quite midday so the heat wasn’t overbearing and there weren’t no heat waves across the fields io make the eye see things funny.

From "Life Is So Good" by George Dawson