The term "parasitoid" literally means a parasite-like organism. While parasites are generally viewed as a wide-range of organisms that feed on a host without necessarily killing it, the term parasitiod usually refers specifically to arthropods (or insects) that kill their host during the feeding phase. Parasitoids differ from predators in that they typically require only one host to complete their development, they are usually not mobile during their immature (parasitic) life stages. Most insect parasitoids are types of wasps or flies.