Definition of "cooldown"

cooldown

/kuːldaʊn/

noun
plural cooldowns
1. (video games) The minimum length of time that the player needs to wait after using an ability or item before it can be used again.
  Quotations
  Private Terminal: After using a power, you must wait for it to recharge before using it again.Private Terminal: This is called the cooldown period. When a power is in cooldown, its icon is gray. A red icon indicates that the power cannot affect the current target.
  2012, BioWare, Mass Effect 3 (Science Fiction), Redwood City: Electronic Arts, PC, scene: Tactical Mastery: Advanced Power Use
2. (sports) The rest period between sets or workout sessions.
3. (by extension) Any rest period between sessions of an activity or event.