Grammar Tip – Hyphens With Prefixes

Sandra’s question: “In words beginning with the prefix ‘pre,’ I am having difficulty determining when to hyphenate and when to state them as one word (or two words if that’s an option), for instance, words such as ‘pre content.’ ”

BizWritingTip response: A prefix is a short word (e.g., anti-, ex-, post-, pre-) placed before another word to modify its meaning. It is attached to the following word or joined to it with a hyphen.

anti-inflammatory     pre-war     pre-content     preheat    antitrust

A prefix cannot sit by itself in a sentence, e.g., pre content. (Note: Your spell checker will not identify this error as the two words in themselves are valid. But it is an error.)

Authorities often differ on whether you need to hyphenate the words or run them together. In American English, the guideline is to avoid the hyphen if you can. British and Canadian English tend to recommend the hyphen more often.

The following are some guidelines for prefixes regardless of what form of English you are using.

1.   Use a hyphen to avoid awkward spelling.
Anti-aircraft (Antiaircraft looks awkward.)

2.   Insert a hyphen to avoid duplicating vowels.
pre-exist     co-operate      re-enter    de-emphasize

3.   Use a hyphen if the following word begins with a capital letter or is a number.
pre-Aids era       pre-Confederation      pro-American forces        post-1920 fashion

4.   Use a hyphen after a prefix when an unhyphenated word would have a different meaning.
re-treat versus retreat     coop versus co-op       re-cover versus recover

5.   Do not use a hyphen if the unhyphenated version is common.
prefix      prehistoric     postoperative   proactive    ultraviolet   nonnegotiable

Bottom Line: If these rules don’t answer your specific question, type the prefix and the following word as one word and then rely on your spell checker – set of course to the English dictionary you prefer.