Unlock

Basics
In Guild Wars "to unlock something" (an item, rune, skill, ...) means to make it available for your PvP characters.

There are different ways to unlock things in Guild Wars:

Unlock through PvE

 * Learning a skill (regardless of whether it's from a Quest, Skill Trainer or Boss) will unlock the skill.
 * Identifying a weapon upgrade or rune from loot will unlock it.
 * Notes:
 * You do not unlock things that you buy, only things that you identify by use of the Identification Kit. This means if you buy a weapon upgrade from a fellow gamer, you will not unlock it, unless it is still "unidentified".
 * Buying a Rune from a Rune Trader will not unlock it. Runes can only be unlocked by using an Identification Kit on Salvage Items such as Ettin's Pauldrons or Seeker's Armors. If you salvage the salvage item before identifying it, you will receive an unidentified Rune.
 * When you identify a weapon upgrade with a higher bonus than you have previously unlocked, you unlock that upgrade with the newer, higher bonus. For example, let's say you have never identified any swords before and you identify a sword that turns out to be a "Fiery Fellblade of Enchanting." This will unlock Fiery Hilt and Sword Pommel of Enchanting with a particular bonus (10...20%) to enchantment length. If it turns out to be 12%, then your PvP characters will have that pommel available to them with the same 12% bonus. If you later identify a sword with a higher bonus, you unlock the higher bonus.

Unlock through PvP
You can spend Faction points gained in PvP at a Priest of Balthazar to unlock skills, runes and weapon upgrades.

For details see: Faction