A hyphen (-) is a punctuation mark used to connect two or more words (or parts of words) to show that they form one unit of sense – e.g., “fast-paced”, “shake-up”, “four-year-old”, “post-punk”.
Mistakes with hyphens are very common: leaving them out when they’re needed, adding them when they’re unnecessary, or putting them in the wrong place. This is mainly because the same series of words may be hyphenated or not depending on the role it plays in a sentence.
This table covers the main guidelines for using hyphens correctly, which are then explained in more detail below.