- The time it takes to recharge after a spell has been cast or an ability or item power has started being used. You will not be allowed to cast another spell for the duration of the cooldown period. This is not the cast time, and usually the cast time of a spell or ability is longer than the animation, which means you can begin your next spell immediately after the cast is finished.
- Potions have a 10 second cooldown.
The term cooldown can also refer to an ability with a long cooldown; for example, Save your cooldowns for boss fights.
A shared cooldown is when some spell, item or ability prevents usage of certain others while it is cooling down. It effectively applies the same cooldown to all those that it shares cooldown with.
It is important to know if a spell or item has a shared cooldown, since that is much more limiting than an isolated cooldown. This usually means that you must choose wisely which to use, since you cannot use all within a short time period. For instance, many potions share cooldown with other potions.
Many skills have elaborate animations, during which the character can not preform any other actions. This, effectively, acts as a cooldown. It can be compared to the global or universal cooldowns found in various other MMOs.
Cooldown and usage theory
The cooldown determines how often something (skill or item) may be used. Specifically, it has an inverse relationship to how many times per fight it may be used. As such, skills with long cooldowns should not be used lightly, but instead saved for when they'd be useful, possibly life-saving.
Items with cooldowns are simply items that have limit on how often you can use them.
For example, many Potions have a 10 minute cooldown, so it can be used just once every 10 minutes.
Most consumable items have a shared cooldown, such as potions.
Most items don't have animations upon use, or ones that can not be canceled by other actions.