Cooldowns are found in many items, skills, and others. For instance, some skills require a cooldown of seconds to minutes for an individual use. After the cooldown is completed, you can reactivate the specific skill again. It has a same system to items and other things found in the game as well.
A broader definition of the term cooldown would simply mean as a period of wait time before a skill, item, or technique can be used after it.
Duration is also found in the game. Durations and cool downs are almost exact. In food, drink, etc. items, they require a duration of how fast the cooking is going to take in the areas of a cooldown. To all other durations, the basic definition is defined as how many seconds it takes for one cooldown.