What defines a parasite?

A parasite is specifically defined as an organism that benefits by living off its host. This relationship typically involves the parasite deriving nutrients and other advantages from the host while causing some level of harm or disadvantage to the host organism. The essence of parasitism lies in this dependency: the parasite relies on the host for survival and reproduction, often at the expense of the host's health or resources.

In parasitic relationships, the benefits gained by the parasite can manifest in various forms, including nutrition, protection, and a suitable environment for reproduction. This interaction is foundational to understanding many ecological and biological dynamics, as it highlights both the complexity of living organisms and the interconnectedness of ecosystems. Understanding this definition helps clarify the nature of interactions between species and their roles in their respective environments.