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Synonyms

hi

1 American  
[hahy] / haɪ /

interjection

  1. (used as an exclamation of greeting) hello!

hi 2 American  
[hahy] / haɪ /

adjective

  1. an informal, simplified spelling of high.

    hi fidelity.
HI 3 American  

abbreviation

  1. Hawaii (approved especially for use with zip code).

  2. Meteorology. heat index. Also H.I.

H.I. 4 American  

abbreviation

  1. Hawaiian Islands.

  2. Meteorology. heat index. Also HI

HI 1 British  

abbreviation

  1. Hawaii (state)

  2. Hawaiian Islands

"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
hi 2 British  
/ haɪ /

  1. an informal word for hello

"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
hi 3 British  
/ haɪ /

interjection

  1. an expression used to attract attention

"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

Etymology

Origin of hi

First recorded in 1425–75; late Middle English hy, perhaps variant of hei hey

Explanation

Hi is a common greeting, more casual than "hello." When you walk down the street in a small town, it might seem like everyone you pass says "hi." The word hi is a good, nearly all-purpose greeting — it's appropriate in all but the most formal circumstances, so you might want to skip saying, "Hi" to the Queen when you meet her. When you greet someone, you have a lot of words to choose from, including "hey," "hello," "hiya," and "howdy," but hi is probably the most common. The first mention of hi attributes it to a Kansas native American in the 1800s.

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Vocabulary lists containing hi

Scrabble: Two-Letter Words

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Spelling Practice 1, Unit 3

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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.

“When you’re out on a run or a walk or a bike ride, do you say hi to people that pass? If you don’t, I’m not so sure about you,” he joked.

From MarketWatch • Apr. 20, 2026

“Oh hi baby,” she captioned a set of baby-bump-baring photos shared to Instagram in November.

From Los Angeles Times • Mar. 18, 2026

Ovitz, the former superagent, says he’ll always stop to say hi, but: “We all know: Don’t hang out.”

From The Wall Street Journal • Mar. 9, 2026

In an email from 2012, Epstein wrote to a publicist, apparently from the Cannes Film Festival, that he was "sitting next to Brett Ratner", adding: "Brett says hi and he loves you!"

From BBC • Feb. 3, 2026

“Delilah, are you—oh, hi, Mom. Why are you home so early?”

From "Maybe He Just Likes You" by Barbara Dee

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.