Interior Architecture is a term used to differentiate between interior decorating and ‘interior design’. This latter term is much abused by people who wander around with sample books and catalogues, that ‘assemble’ an interior but don’t (in the strictest sense of the word) actually ‘create’ anything.
This is Interior decorating and is generally about using things you buy from shops to change a space. Interior architecture (or interior design) also involves creating unique things you have to build as well as things you buy.
Think of an interior decorator as like a nurse, and an interior architect as like a doctor, and be wary of the term ‘interior designer’.
Interior architects have spent a lot longer qualifying, and have much more detailed knowledge. The term is used because like architects, they are professionals, and need to be licensed and governed by national or regional institutes. This is a contrast to interior decorators (who sometimes call themselves interior designers) who can have completed an online course in a few weeks for a qualification.
There is nothing wrong with interior decorating at all. There are some excellent ones, and there are instances where one might be preferable to and interior architect, but you need to know the difference.3.6k views.
A source: Quora.