The word "interior" relates to the inside of something. Several definitions exist with slight variations but most have to do with an inner part. A slight exception is the definition that means "domestic," as in the interior affairs of a nation, but even that means affairs dealing with internal issues.
In other uses, the interior of a house refers to its inside parts, and the interior view of a dishwasher relates to looking at the inside of it. The interior part of a country is the part more toward the center and away from the borders. The prefix "inter-" originates from the Latin meaning "inward," and the "ior" part of the word is a comparative suffix. The word literally means "more inward."