Cooldown reduction is a bonus stat which can be received by buying Rune Boots, Wizard's Hourglass or Runed Scepter. It reduces the cooldowns of the hero's spells, active items, and even pet abilities (including the passive).
Cooldown Reduction StackingEdit
Cooldown reduction stacks multiplicatively:
Max cooldown reduction from all 3 CDR items will be 45.37%