adjective
internal
in-TUR-nul/ɪnˈtɜːrnl/
Existing or happening inside something.
The clock's internal gears sit entirely within its outer casing.

Etymology
The inward sense of internus remains central: internal first described something extending toward the interior, then something situated within it.
In context
The internal body scan will reveal if the passenger is bringing back more than just silicon buttock implants inside her body.
More examples
- Doctors check for internal bleeding after the accident.
- The company conducts an internal review of its hiring practices.
- Removing an internal wall makes the kitchen feel larger.
Forms
internally adverb — On the inside or within something.