The biological interaction in which one organism (the predator) hunts, kills, and eats another organism (the prey) for energy is known as predation.
Predators use their prey as a source of food. Predation is different from parasitism because the prey is killed immediately for consumption. During parasitism, the host is kept alive for a long period of time so that the parasite can continue to receive nutrients from the host.
An example of predation is a cheetah hunting, killing, and consuming a gazelle.