The word "parasite" refers to an organism that lives on or inside another organism (the host) and benefits at the host's expense. Parasites can cause harm to their hosts by stealing nutrients, harming tissues, or spreading diseases. This term is also used metaphorically to describe a person or entity that takes advantage of others without contributing anything in return.
The word "parasite" comes from the Greek word "parasitos," which means "one who eats at the table of another." It is derived from "para-" meaning "beside" and "sitos" meaning "food."