This is a word of Greek origin. The prefix [epi] means "outer" or "above"; the root term [-thel-] means "nipple" or "female", and the suffix [-ium] means "layer" or "membrane.  The reason for the origin of this words is that in c.1700 Ryusch used this term to refer to the surface layer of cells in the nipple and areola. It was later used to denote any covering superficial layer of cells.  The plural form for epithelium is epithelia.

There are many types of epithelia in the body, and they are described by their histology, or how they look under the microscope: single-layer, multilayered, cuboidal, columnar, etc.

- Although the above is the standard accepted etymology for this word, I have a different interpretation, as the Latin term [tela], meaning "fabric" or "cover" could have been used. Thus explained, the word means "outer cover layer". Who knows?. Dr. Miranda -

"The origin of Medical Terms" Skinner, AH, 1970

Abraham Vater (1684 - 1751) German anatomist and physician, Abraham Vater was the son of a distinguished physician and was born on the city of Wittenberg. He obtained a Doctorate in Philosophy (PhD) in 1706 and his medical degree in 1710 at the University of Leipzig. He became a professor “extraordinarius” of Anatomy and Botany in 1719, continuing his career in anatomy until he obtained the highest professorial degree at the University.

The word [epicardium] is composed by the prefix [epi-], meaning "outer" or "above"; the root term [-card-], meaning "heart"; and the suffix [-ium], meaning "layer" or "membrane". Thus, the word means "outer layer of the heart".

The epicardium is part of a larger structure called the pericardium, in fact, since the pericardium is in contact with a viscus (the heart), it can also be called "visceral pericardium". It must be noted that these two terms are synonyms: "epicardium" and "visceral pericardium".

The epicardium is a type of serosa composed of an outer layer formed by mesothelial cells and an inner layer formed by loose connective tissue containing varying amounts of fat. This inner layer known as the "subepicardial layer" (a misnomer) also contains elastic fibers.

As a serosa, the epicardium is involved in the production and absorption of a clear fluid, the "pericardial fluid". This fluid acts as a lubricant for the pericardium, allowing for the effortless movement of the heart within the pericardial sac.

The suffix [-iasis] has an original Greek root (such as in [iatros] meaning "healer" or "hospital"). It later became a Latin root meaning "condition, pathology, or disease".

This suffix can be found in many medical terms such as:

• Choledocolithiasis - a condition of stones in the bile duct.
• Elephantiasis - A condiction where a body part grows unusually large, usually lower extremities and/ or scrotum
• Phthiriasis- A condition or infestarion with public or crab lice
• Helminthiasis- Anbodily infestation with a type of parasitic worms called helminths (tapeworms)
• Cystolithiasis -  Bladder stones