Internal (adjective) — related to the inside of something, particularly the body; opposite of external.
Refers to something occurring inside a physical body or within a group or organization, contrasting with external or outside influences.
“Connected with the inside of your body; involving or affecting only the people who are part of a particular organization.”
— Oxford Learner’s Dictionaries
Describes something existing or happening within a body or organization, highlighting contrast with external or outside aspects.