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

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.

The online service Grammarly originated in 2009 as a suite of tools to help ferret out plagiarism in schoolwork or help students hone their grammar and spelling.

From Los Angeles Times

Activism isn’t just about wielding guns and throwing rocks but organizing online, in the classrooms and among households.

From Los Angeles Times

Michael Terry, an institutional investment manager who used the terminal for more than 30 years, said he used a prompt circulating online to try to vibe code a Bloomberg replica on Anthropic’s Claude.

From The Wall Street Journal

She said she had to declare the age of her car in the online application for the role at haart as a question asked, "is your car under 10 years old" and she ticked "no".

From BBC

Revolut encourages customers to use an online chat forum to deal with its customer service agents.

From BBC