Interior Wall
An interior wall is any wall inside the building envelope that divides or defines internal spaces, as distinct from an external wall that forms part of the building's weather-facing skin.
Interior walls fall into two broad categories. Loadbearing walls carry structural load from above, such as floor or roof framing, down to the footings. Non-loadbearing walls, often called partitions, divide space only and can generally be moved or removed without structural consequence.
Knowing which is which governs what is possible in a renovation. Removing a loadbearing wall to open up a living area is entirely achievable, but it requires a beam, engineering, and support back to a footing, which changes the cost and the program.
Interior walls also do quiet work: they conceal services, provide acoustic separation between bedrooms and living areas, brace the structure against lateral load, and set the fire separation between parts of a building or between attached dwellings.