From Elsmar Cove Quality Assurance and Business Standards Wiki
Interchangeability - The ability of an entity to be used in place of another without modification to fulfill the same requirements.
1. A qualifier such as "functional interchangeability" or "dimensional interchangeability"
should be used depending on specific circumstances.
2. The above definition is valid for the purposes of quality standards.
The term "interchangeability" is defined differently in ISO/IEC Guide 2.