Term used to describe a word that is broken up with a hyphen when it reaches the edge of a document. Below is a basic example of hyphenation, as can be seen the word "service" is hyphenated.

Computer Hope is a free ser-
vice that helps users with their
computer related questions.

How to enable hyphenation in Microsoft Word

By default Hyphenation is set tot None in Microsoft Word, which prevents hyphenation from occuring. If you want to adjust the hyphenation settings click on the Page Layout tab, Hyphenation, and then select "Automatic" from the list.

Hyphenation in Microsoft Word

Also see: Conditional hyphen, Dash, Word wrap