Using Hyphens in Compound Adjectives - Part 1

Hyphens are used to join the words in compound adjectives. A compound adjective is a single adjective made up of more than one word. For example (compound adjectives in bold):

• free-range eggs

• far-too-chatty individual,

• eight-seater taxi

In the UK, readers will expect you to use hyphens to link the words in your compound adjectives, but, in the US, readers are more lenient. That said, regardless of which convention you're using, if you're comfortable with spotting compound adjectives, then you should group them with hyphens (or, occasionally, capital letters, italics, or quotation marks). This will: (1) Make it easier to read. (2) Showcase your writing skills a little. (3) Remove the possibility for ambiguity. When the unhyphenated version of a compound adjective is ambiguous, you must use a hyphen(s) to link its words. For example:

• a small business grant (Is this a small grant for business purposes or a grant for a small business?)

• a small-business grant (The hyphen makes it clear this is a grant for a small business. It could be a large grant.)

• a heavy water reactor (Is this a heavy reactor for use with water or a heavy-water reactor?) (Note: "heavy water" is deuterium oxide.)

• a heavy-water reactor (The hyphen makes it clear this is a deuterium-oxide reactor.)

• a fast evolving car (Is this car fast or evolving fast?)

• a fast-evolving car (The hyphen makes it clear the car is evolving quickly.)