Online and Offline: To Hyphenate or Not

Sheila Sanders
(Terminology Update, Volume 34, Number 3, 2001, page 28)

Languages evolved at a much slower pace before the advent of computers. This new technology revolutionized the way we communicate, changing not only our lives but also everyday and specialized language. Multiword terms such as on line and off line, which only a few years ago were written as separate words, are now hyphenated or written as one term.

Unable to keep up with the latest trends, dictionaries and usage guides often give conflicting information. Computer lingo is in limbo. And to complicate matters, the written form that applies to Canada and the United States is often different from British spelling. Yet just because terminology is in a state of flux, it doesn’t mean that a word can be written in any fashion. The rules may be changing but they do exist, though they are often applied with a light-hearted, dynamic approach.

The terms on line and off line are instances of the rapid transformation in form. Originally they were written as separate units, as in:

  • Jeremy can’t find the off line readers site.
  • Barb was pleased to discover that she could research her genealogy on line as well as off line.

Now it is far more common to see on line and off line hyphenated, both as adjectives and adverbs:

  • Gwen liked using an on-line guitar archive as a source for new songs.
  • What are on-line and off-line signatures?

Among the sources consulted, the 1995 edition of Collins Cobuild English Dictionary lists both online and on-line, with on line as an adverb phrase; it has no entry for offline. According to the Gage Canadian Dictionary, 2000, the use of on-line or online is optional, but off-line is the recommended spelling. The Canadian Oxford Dictionary, 1998, records on-line and off-line for both adjective and adverb, while TERMIUM® documents usage for all variants. The 11th edition of the Dictionnaire d’informatique anglais/français by Michel Ginguay lists the two terms as both separate words and hyphenated ones, but all except one of the adjectival examples are hyphenated. The lack of agreement among sources and the fact that computer language is in transition are apparent.

Other references, including The Canadian Press Stylebook, Information Technology Vocabulary (published by the Canadian Standards Association), and the International Organization for Standardization (ISO/IEC WD1 2382-01, 1998-06), confirm the use of the solid words online and offline. However, on-line and off-line have also been standardized by ISO for Great Britain. In other English-speaking countries, the preference is the unhyphenated spelling, as in:

  • This chart was created from Statistics Canada’s online statistical database.
  • Many consumers enjoy the convenience of banking online.

Another source, the Prentice Hall Canada Reference Guide to Grammar and Usage, lists online but has no reference for the less common offline.

Researching everyday usage in the search engine Google revealed that Canadians write both these terms as solid words approximately three times more often than the hyphenated version, but Canadian government texts show a slight preference for the hyphenated versions on-line and off-line.

Where does that leave the average writer who simply wants to quickly determine whether to write on line, on-line or online (and off line, off-line or offline)? Writing these terms as separate words is no longer popular and does not reflect current practice. Online and offline may be written either with or without a hyphen. The rule, of course, is consistency: use the same form throughout a document. The normal progression in English is to move from two separate words, to a hyphenated word, to a single term. Thus, online and offline are no exceptions; they are simply moving through these stages very quickly. In this article, online and offline are written as compound words, reflecting the author’s belief about their ultimate spelling.

To further highlight this normal progression, the sources below are arranged according to the two recommended spellings for online. When a source offers both, it is categorized according to its first choice.


  • Chicago Style Web site
  • Dictionnaire anglais/français des télécommunications et de l’Internet (1999)
  • Gage Canadian Dictionary (2000)
  • Merriam-Webster’s Collegiate Dictionary (1998)
  • The Canadian Oxford Dictionary (1998)
  • The Globe and Mail Style Book (1998)
  • The Gregg Reference Manual (1999)
  • The Penguin Canadian Dictionary (1990)


  • Dictionnaire d’informatique anglais- français (IBM,1994)
  • E-What? A Guide to the Quirks of New
  • Media Style and Usage (2000)
  • Information Technology Vocabulary (CSA, 1992)
  • International Organization for Standardization (ISO, WDI 2382-01 1998)
  • Language International (Vol. (Terminology Update, Volume) 13, No. 1, 2001)
  • Microsoft Press Computer User’s Dictionary (1998)
  • The BBI Dictionary of English Word Combinations (1997)
  • The Canadian Press Stylebook (1999)
  • The Prentice Hall Canada Reference Guide to Grammar and Usage (1997)
  • Wired Style Principles of English Usage in the Digital Age (1999)

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