IPA: /ɪnˈtɜrnəl/
KK: /ɪnˈtɜrnəl/
Relating to something that is inside or within a particular area, such as the body, mind, or organization.
The internal structure of the building was just as impressive as its exterior.
Internal → It is formed from "inter-" (meaning between) and "nal" (from Latin "internus", meaning within). The word "internal" refers to something that is situated within or inside something else.
Think of something that is 'within' ('internus') — that's why internal means something that is inside.