endo-, end- (10/32)

The medical prefix term end(o)- means “inside”.

Example Word: end(o)/metr/i/um

Word Breakdown: End(o)- means “inside”,  metr/i is a combining form that refers to the “uterus”, -um is a noun ending suffix with no specific meaning.

Definition: Endometrium is the innermost lining layer of the uterus.

More Examples of Medical Terms Starting in Endo-

Endocardium: endo– (“inner” or “within”) + cardi (“heart”) + –um (“pertaining to”).

Definition: The inner layer of the heart, consisting of a thin membrane lining the chambers of the heart and surrounding the heart valves.

Endocrinology: endo– (“inner” or “within”) + crin/o (“to secrete”) + –logy (“the study of”).

Definition: The study of the glands that produce hormones to regulate the body’s functions.

Endodontics: endo– (“inner” or “within”) + odont (“tooth”) + –ics (“pertaining to”).

Definition: Branch of dentistry concerned with diagnosis and treatment of diseases and injuries of pulp and root of tooth.

Endometriosis: endo– (“inner” or “within”) + metr (“uterus”) + –osis (“abnormal condition”).

Definition: Condition in which tissue similar to lining of uterus grows outside of uterus, often causing pain and fertility issues.

Endomyocardium: endo– (“inner” or “within”) + my/o (“muscle”) + cardi (meaning “heart”) + –um (suffix indicating “pertaining to”).

Definition: The inner layer of the heart muscle.

Endonuclease: endo– (“inner” or “within”) + nucle (meaning “nucleus”) + –ase (“enzyme”).

Definition: An enzyme that breaks down the bonds within nucleic acids, such as DNA and RNA.

Endophthalmitis: endo– (“inner” or “within”) + ophthalm (meaning “eye”) + –itis (indicating “inflammation”).

Definition: Inflammation of the inner structures of the eye, including the vitreous humor and the retina.

Endoplasm: endo-” (“inner” or “within”) + –plasm (“living substance” or “tissue”).

Definition: The inner, more granular portion of the cytoplasm in some cells, containing organelles such as ribosomes, mitochondria, and lysosomes.

Endorphin: end– (“inner” or “within”) + –orphine (meaning “morphine”).

Definition: A hormone produced by the pituitary gland that acts as a natural painkiller.

Endoskeleton: endo– (“inner” or “within”) + skeleton (“skeleton”).

Definition: An internal skeleton, as found in many invertebrates such as insects and crustaceans.

Endothelium: endo– (“inner” or “within”) + theli (meaning “lining”) + –um (“pertaining to”).

Definition: The inner lining of certain body cavities, such as the blood vessels, lymphatic vessels, and heart.