(anatomy) An organ, such as the heart or colon, that is entirely within the confines of the body.

plural of barrel organ

(biology) Any organism (e.g. the fruit fly) that has been extensively studied as an example of many others, and from which general principles may be established

A person (living or dead) from whom an organ is removed in order to be transplanted into another person. / (chiefly US, slang) A motorcyclist, especially one who does not wear a protective helmet.

Alternative spelling of microorganism

plural of vital organ

An organ of the body which performs a sufficiently important function that damage to the organ can cause death.

(music) A type of electronic organ with a highly distinctive sound.

An organization with charitable purposes only.

(music) Any kind of electronic musical instrument which can emulate the sound of any of the tonewheel-based Hammond organs.