Parasite - Origin of the Word

The mitochondria that produce energy in our cells were
 once free-living organisms. Diagram by Boumphreyfr
     CC BY-SA 3.0

Parasite comes from the Greek word meaning “one who eats at the table of another.” The term is a social one, used in ancient Greece - and still today - to refer to people who get what they need by exploiting others. I’ve seen parasite used to describe various freeloaders, politicians, government employees, tax evaders, control freaks and pimps. It’s never meant as a complement.

At some point people must have recognized the similarity between the social parasites that plagued them and the animal ones that they observed living off other animals. They saw this as a negative thing – a way of life to be despised, and they gave it a negative label. Little did they know that parasitism is a time honoured way of life, a very successful way of life, and something to which they owed their very existence.