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  • io
    io
    noun
    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.
  • Io
    Io
    noun
    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.
  • Io.
    Io.
    abbreviation
    Iowa.
  • I/O
  • I.O.
    I.O.
    abbreviation
    indirect object.

io

1 American  
[ee-oh] / ˈi oʊ /
Or 'io

noun

  • ios
    plural
  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.


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.


Io 3 American  
[ahy-oh, ee-oh] / ˈaɪ oʊ, ˈi oʊ /

noun

  • Ios
    plural
  1. Io moth.


Io 4 American  
Symbol, Chemistry.
  1. ionium.


Io. 5 American  

abbreviation

  1. Iowa.


I/O 6 American  
I.O. 7 American  
Or IO,

abbreviation

  1. indirect object.


I/O 1 British  

abbreviation

  1. input/output

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Io 2 British  

symbol

  1. ionium

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Io 3 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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

io 4 British  

abbreviation

  1. British Indian Ocean Territory

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Io 5 British  
/ ˈaɪəʊ /

noun

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

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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


Other Word Forms

Noun Inflected Forms

Etymology

Origin of io

From Hawaiian ʿio

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

OpenAI bought that company, io Products, in 2025 to spearhead its own device development efforts.

From The Wall Street Journal ● Jul. 12, 2026

Tan spent 24 years at Apple, most recently as vice president of product design for the iPhone and Apple Watch, before co-founding io Products, which OpenAI acquired for roughly $6.5 billion in 2025.

From Barron's ● Jul. 10, 2026

Along with OpenAI, Apple is suing io Products, the design startup founded by Jony Ive, a long-time Apple executive.

From BBC ● Jul. 10, 2026

Tan left Apple to found io Products alongside Jony Ive, Apple’s former chief design officer, and other leaders.

From MarketWatch ● Jul. 10, 2026

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

This effect is dramatic on Io, Jupiter's innermost large moon, where intense gravitational stretching drives constant volcanic eruptions.

From Science Daily ● Jan. 7, 2026

“The intriguing feature could improve our understanding of volcanism not only on Io but on other worlds as well.”

From Salon ● Feb. 3, 2025

The acid yellow moon Io that orbits Jupiter may be less than 30% the size of Earth, but is considered the most volcanic body in our solar system.

From Salon ● Feb. 3, 2025

The spacecraft produced the first high-resolution images of the four planets, the rings of Jupiter, Uranus and Neptune, lightning on Jupiter and lava lakes that revealed active volcanoes on Jupiter’s moon Io.

From New York Times ● Jun. 14, 2024

The surface of Io is changing on a time scale of months.

From "Cosmos" by Carl Sagan

They are, however, frequently abbreviated thus: Iowa, Ia. or Io.;

From Higher Lessons in English A work on English grammar and composition by Brainerd Kellogg

The I/O event was “almost entirely commercially driven,” according to Windsor.

From MarketWatch ● May 20, 2026

Gmail Live, announced at this week’s Google I/O conference, allows you to ask your inbox questions aloud, like what’s your flight reservation number or the door code to your Airbnb.

From The Wall Street Journal ● May 19, 2026

The order is for production of wafer-level test and burn-in of silicon photonics integrated circuits, used in data center optical interconnects and emerging optical I/O architectures for AI processors, according to Aehr.

From Barron's ● Apr. 3, 2026

In the months leading up to I/O, search engine optimization experts found that the Google Search algorithm had made some drastic updates.

From Slate ● May 16, 2024

In Great Britain, `fred', `jim' and `sheila' are common metasyntactic variables because their uppercase versions were official names given to the 3 memory areas that held I/O status registers on the lovingly-remembered BBC Microcomputer!

From The Jargon File, Version 4.2.2, 20 Aug 2000 by Guy L. Steele

The senior coalition officer said the insurgents who supported the Qatar process “didn’t do a good I.O. campaign to sell it to their people.”

From New York Times ● Oct. 2, 2012

To these three the President added Sidney Hillman, pink-cheeked, blond, curly-haired, 53, chief of Amalgamated Clothing Workers of America, vice president of C. I.O., a "labor statesman," no bumbler, coldly intellectual.

From Time Magazine Archive

Mr. Green next day notified the Canadian Trades and Labor Congress that it must expel 30,000 C. I.O. members or renounce 120,000 A. F. of L. members.

From Time Magazine Archive

Between A. F. of L. and C. I.O. there still exists a thin, technical tie: the rebellious C. I. O. unions were suspended last year but they have not yet been expelled.

From Time Magazine Archive

I see them shaking their fists in the face of the parietal tutor.—Oration before H.L. of I.O. of O.F.,

From A Collection of College Words and Customs by Benjamin Homer Hall

Preparations are under way to repatriate the remains of two teenagers from Dublin who died in separate incidents on the Greek island of Ios over the weekend.

From BBC ● Jul. 4, 2023

Post-mortem examinations are to be carried out on Tuesday on two teenagers from Dublin who died on the Greek island of Ios.

From BBC ● Jul. 3, 2023

Athens natives, the couple first came to Ios in 2003 for a family vacation.

From New York Times ● Aug. 24, 2022

In October, they interrogated a submarine cable that connects the islands of Santorini and Ios.

From Science Magazine ● Dec. 8, 2021

The Pythia answered: 'The Isle of Ios is your mother's country and it shall receive you dead; but beware of the riddle of the young children.'

From Hesiod, the Homeric Hymns, and Homerica by Hugh G. (Hugh Gerard) Evelyn-White

This week the app overtook WeChat and TikTok to become the most-downloaded app for Apple and ios devices in China, though its popularity is not entirely due to merit.

From The Guardian ● Feb. 15, 2019

There are a lot of closeups and  difficult-to-decipher geometry, but the intent here is clear — Sony is ios going to show us what the PS4 actually looks like.

From Forbes ● May 20, 2013

Android is much better, in my opinion, because it is not afraid to make drastic changes to its system. ios has looked similar since the start.

From Time ● Apr. 21, 2013

The price is 28,000 10000 in fives and ios 18000 50 and zoos.

From Time Magazine Archive

Only the brooding golden backlighting that makes theaters out of Parrish's scenar ios bespeaks a pre-neon sensibility.

From Time Magazine Archive

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