Experience Points, usually abbreviated as EXP/Exp, are a recurring feature of the Dragon Quest series. Experience Points have been present in every main series game and nearly all spinoff games.
Experience Points are gained at the end of a random encounter or other battle as a reward. More powerful monsters reward greater amounts of Experience Points.
When a character accrues a specific, predetermined number of Experience Points, they will "level up" (that is, gain a level of experience) and receive statistical increases particular to their overall character type. In most games, this is characteristic of the party member, though in Dragon Quest III: The Seeds of Salvation and Dragon Quest IX: Sentinels of the Starry Skies stat growth is dependent on the character's Vocation.
Alternatively, a character wearing the elevating shoes gain an experience point for each step made out of battle. This accessory can be found in Dragon Quest III: The Seeds of Salvation, Dragon Quest IV: Chapters of the Chosen, Dragon Quest VII: Fragments of the Forgotten Past, Dragon Quest VIII: Journey of the Cursed King and Dragon Quest IX: Sentinels of the Starry Skies.
Also, the King of Burland grants Ragnar McRyan some experience points at the end of Dragon Quest IV Chapter 1.