external Definition

capable of being perceived outwardly

having merely the outward appearance of something : superficial

not intrinsic or essential

something that is external: such as

an outer part

an external feature or aspect —usually used in plural

a heat engine (such as a steam engine) that derives its heat from fuel consumed outside the cylinder

a degree conferred on a student who has not attended the university but has passed the qualifying examination

exchange of gases between the external environment and a distributing system of the animal body (such as the lungs of higher vertebrates or the tracheal tubes of insects) or between the alveoli of the lungs and the blood