A fictional term used in the latest Star Wars movie.
Midi-chlorians, as explained by the creator of Star Wars, George Lucas:
"Midi-chlorians are a loose depiction of mitochondria, which are necessary components for cells to divide. They probably had something--which will come out someday--to do with the beginnings of life and how one cell decided to become two cells with a little help from this other little creature who came in, without whom life couldn't exist. And it's really a way of saying we have hundreds of little creatures who live on us, and without them, we all would die. There wouldn't be any life. They are necessary for us; we are necessary for them. Using them in the metaphor, saying society is the same way, says we all must get along with each other."
In reality these are called mitochondrion.
Mitochondria are an essential part of all living cells. They convert the nutrients (primarily carbohydrates and fatty acids) into adenosine triphosphate or ATP, the "energy currency" that your cells - and your entire body - operate on....