Heart Container
Link's health is symbolized throughout the Zelda series (excluding Adventure of Link) as a set of Hearts. As Link progresses through the games, he will require more and more health in order to survive the greater challenges. This additional health is acquired in the form of Heart Containers. A Heart Container is awarded after every major boss in the games, and can also be manually built by acquiring four (or five in Twilight Princess) Pieces of a Heart.