internal
adj.adj. located on the inside of something, like your body or a building. It can also describe things that happen within a single group or company.
adj. situated or occurring within the interior of a structure, organism, or organization. Often used in medical contexts to describe organs or in business to describe private affairs.
The doctor checked for internal injuries after the accident.
The company launched an internal investigation to find out why the computer system failed.
While the external facade of the cathedral appears Gothic, the internal structural supports were reinforced with modern steel during the restoration project to ensure long-term stability.
From Middle English internall, internalle, borrowing from New Latin internālis (“of or pertaining to the inner part”), from internus (“inward, internal”) + -ālis (“-al”, adjectival suffix). By surface analysis, intern + -al.
Typically placed before the noun it modifies; frequently contrasted with 'external'.