The use of hyphens to break words across lines to manage spacing variations in justified text, the evenness of unjustified line breaks, and words that would not otherwise fit on the measure.

In typesetting terms, hyphenation is the method of breaking words across lines, indicated by a hyphen at the break point. It is a complicated balancing act between typographic and linguistic concerns.

In general linguistic terms, hyphenation also refers to the use of hyphens to join compound words or phrases.

The typographic decision-making process is handled in several ways.

  1. Algorithms that attempt to make decisions based on a complex series of language-dependent rules. These often use syllabification as a big part of the logic.
  2. Dictionaries that compare the text to a set of predefined logical, weighted word breaks. In software, these can be application-based or operating system wide and can, in most cases, be modified by the user.
  3. A combination of algorithms and dictionaries, most commonly.
  4. Manually applied hyphens and line breaks placed by a typographer to fine tune spacing.
  5. Manually applied discretionary hyphens that the software will resort to as necessary.
  6. A combination of all of the above, in the most demanding typesetting environments.