Campaign

A campaign is a stand-alone component of Guild Wars. Each campaign shares core content, but has its own storyline, skills, armor, and locations.

Campaigns
Guild Wars is currently made up of 3 campaigns:
 * Guild Wars Prophecies (April 2005)
 * Guild Wars Factions (April 2006)
 * Guild Wars Nightfall (October 2006)

According to the store, only these three are actual campaigns.

Expansions
Two expansions are available for Guild Wars: An expansion is different from a campaign in that it is not stand-alone. Expansions can only be added to accounts that include at least one campaign.
 * Guild Wars Eye of the North (August 2007), which provides content similar to a full campaign.
 * Guild Wars Bonus Mission Pack (November 2007), adding four missions retelling historical events.

For lack of a better word, the term campaign is sometimes used to include expansions as well.

Guild Wars Beyond
Guild Wars Beyond is an "ongoing campaign" of updates, adding free content to bridge the gap between Guild Wars and Guild Wars 2.

The official use of the term "campaign" has caused some confusion; Beyond cannot be added to an account and it is not stand-alone. It does not provide additional character slots or storage panels, and it does not satisfy the campaign requirements for adding expansions. Due to the difference, "campaign" in Guild Wars Beyond marketing may refer to a different usage of the word - that of an organized course of action to achieve a particular goal, rather than in the specific context of Guild Wars.

Beyond is split into several storylines or chapters, each having different requirements:
 * War in Kryta requires owning Prophecies and Eye of the North, and completion of one of the two.
 * Hearts of the North requires owning Prophecies and Eye of the North and having completed War in Kryta.
 * Winds of Change requires owning and completing Factions.

Trivia

 * At one time, chapter was used synonymously with campaign. This changed after ArenaNet decided to make the campaigns stand-alone.
 * A fourth campaign, Utopia, was canceled early in its development in favor of Guild Wars 2.
 * The first campaign, Guild Wars Prophecies, is simply Guild Wars as a product in stores.