Disambiguation pages are used as a process of resolving conflicts in article titles that occur when a single term can be associated with more than one topic, making that term likely to be the natural title for more than one article. In other words, disambiguations are paths leading to different articles which could, in principle, have the same title.
For example, the word "Trill" can refer to either the race of people Trill or the planet Trill. Since only one page can have the generic name "Trill", unambiguous article titles are used for each of these topics. There must then be a way to direct the reader to the correct specific article when an ambiguous term is referenced by linking, browsing or searching; this is what is known as disambiguation.