10.1.8. Dashes and hyphens

Dashes may replace commas or brackets, while hyphens are used for compound nouns and adjectives, for prefixes, related or contrasting pairs, and to replace ‘to’ in a number or date range.

1. Dashes. Short (or en) dashes may be used to punctuate a sentence instead of commas or brackets (see Sections 10.1.6(c) and 10.1.7(a)). They increase the contrast or emphasis of the text thus set off. However, use sparingly; use no more than one in a sentence, or – if used with inserted phrases – one set of paired dashes. Avoid using dashes in legislation.

   When citing titles of publications or documents, use an en dash to separate the title from the subtitle.

   The long (or em) dash can be used as a bullet point in lists (see Section 5.7).

2. Hyphens. As a general rule, the form used on the Oxford Dictionaries Premium website (subscription required), or on the Oxford Learner’s Dictionaries website, should be followed (making sure in each case that the British English dictionary is selected).

   1. Hyphenate:

      • nouns composed of a participle plus preposition:

        They discussed the buying-in of sugar.

      • compound adjectives preceding the noun that they qualify:

        up-to-date statistics, long-term policies, foot-and-mouth disease

        Exception: value added tax.

      Do not hyphenate:

      • adverb-adjective modifiers when the adverb ends in -ly:

        an impossibly complex issue

        a pleasantly cool breeze

      • adverb-adjective modifiers when ‘ever’ is followed by a comparative adjective:

        ever closer union

        Many phrases are treated as compounds, and thus need a hyphen, only when used as modifiers:

        up-to-date statistics, but the statistics are up to date

        long-term effects, but effects in the long term

        Other adjectives always take a hyphen:

        carbon-neutral energy sources, and energy sources that are carbon-neutral

   2. Prefixes also take a hyphen:

      anti-American, non-cooperative, co-responsibility levy, co-funded, self-employed

      unless the prefix has become part of the word by usage:

      cooperation, coordination, subsection, reshuffle, email

   3. Either en dashes or hyphens are used to join related or contrasting pairs:

      the Brussels–Paris route / the Brussels-Paris route

      a current–voltage graph / a current-voltage graph

   4. Either en dashes or hyphens are used to replace the word ‘to’ in a number or date range:

      2010–2014 / 2010-2014