Is it online, on line or on-line?

These days, when talking of the Internet world, most writers will use ‘online’ and this denotes something being on the Internet.

Way back, when the phrase first emerged, three forms were seen in written communications.

  • on line
  • on-line
  • online

It started as two words, then became hyphenated, then became a closed compound, as shown above.

  • If you look here, you will see how two-part nouns change to serve as closed compound nouns, often going through the etymological change over several years.

The term has now stuck as: online

When it comes to adjectives, the use of the hyphen in other compounds is vital to recall, however. It is very important and applies right across English.

Where a phrase is just a factual statement, we used two words.

  • My car is now on site.
  • The plan is taking place in the long term.

Where the entire phrase is used to further describe something else, we used the hyphen to show this.

  • This is an on-site car park.
  • The plan is taking place in the long term.

Where the entire phrase is used to further describe something else, we used the hyphen to show this.

  • This is an on-site car park.
  • This is a long-term plan.

See more about long term and long-term.