Dictionary.com
Thesaurus.com

online

American  
[on-lahyn, awn-] / ˈɒnˈlaɪn, ˈɔn- /
Or on-line,

adjective

  1. operating under the direct control of, or connected to, a main computer.

  2. connected by computer to one or more other computers or networks, as through a commercial electronic information service or the internet.

  3. of or denoting a business that transmits electronic information over telecommunications lines.

    an online bookstore.

  4. available or operating on a computer or computer network.

    an online dictionary.

  5. by means of or using a computer.

    online shopping.

  6. Radio. (of a network) supplying affiliated stations with all or a substantial part of their programming.

  7. Television. of or relating to the final editing of a videotaped program.

  8. done or accomplished while in operation or active service.

    online maintenance.

  9. located on major routes or rail lines.

    online industries.


adverb

  1. with or through a computer, especially over a network.

online British  
/ ˈɒnˌlaɪn /

adjective

  1. of, relating to, or concerned with a peripheral device that is directly connected to and controlled by the central processing unit of a computer

  2. of or relating to the internet

    online shopping

  3. occurring as part of, or involving, a continuous sequence of operations, such as a production line

"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

adverb

  1. while connected to a computer or the internet

"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
online Scientific  
/ ŏnlīn /
  1. Connected to or accessible by means of a computer or computer network.


online Cultural  
  1. A term referring to locations on or use of the Internet. The term can be used to refer to a specific location or Web page (“Our sales catalogues can be found online at — ”) or to a personal activity (“I went online to find the information you wanted.”)


Etymology

Origin of online

First recorded in 1915–20 (in sense “located on rail lines”); 1945–50 for other senses

Explanation

When you're online, you are using a computer or other device that's connected to the Internet. If someone asks if you're online, they're wondering whether you have Internet access. You might say, "I need to go online and check my email," or "I don't know if she's still meeting me — she hasn't been online all day." Or you could describe something that's available or readable on the Internet, like a news story, as being online. While the adjective officially describes a connection to any computer network, it's almost always used these days to mean "on the Internet." The word online has been around since 1950.

Keep Reading on Vocabulary.com

Vocabulary lists containing online

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 online shopping, you don't get feedback very quickly," Voon says.

From BBC • May 1, 2026

Over the last decade, videogame retailer and original meme stock GameStop has struggled to contend with the dominance of online gaming, and its sales have declined.

From MarketWatch • May 1, 2026

Cohen, the co-founder of online pet-products retailer Chewy, gained a cult following after he built a big GameStop stake and in late 2020 criticized the company for moving too slowly toward e-commerce.

From The Wall Street Journal • May 1, 2026

Jackie and Shadow have drawn widespread attention in recent years through a live trail camera operated by Friends of Big Bear Valley, which streams their nesting activity to thousands of viewers online.

From Los Angeles Times • May 1, 2026

If I will be able to bring Courage back online.

From "A Rover's Story" by Jasmine Warga