What's another word for interior?

Another word for interior depends on whether you mean noun or adjective. As a noun meaning inside space, synonyms include inside, inner part, inner space, inner side, core, center, heart, inner area, and internal area. For example, interior of a house can be called inside of a house or inner part of a house. As a design term, interior can be called inner decor or inside design, though interior design is standard. As an adjective meaning located inside, synonyms include inner, internal, inside, inward, indoor, and innermost. For example, interior walls can be called inner walls or internal walls, interior door can be called inner door or inside door. For figurative meaning of inner thoughts or character, synonyms include inner self, inner being, psyche, soul, and internal world. In geography, interior meaning inland can be called hinterland, inland area, or heartland. Opposite of interior is exterior. So most common other words are inside for noun form and inner or internal for adjective form. For example, you can say inner space instead of interior space, and people will understand you mean the inside.