noun
interchangeability; interoperability
Technical computing term referring to the ability of different systems or components to work together or be used in place of one another.
このソフトウェアは相互互換性が高いため、異なるOSでも同じデータが使えます。
This software has high interoperability, so the same data can be used across different operating systems.
互換性 means compatibility in a broader sense, while 相互互換性 specifically emphasizes mutual interchangeability between two or more systems.
Compound of 相互 (mutual) + 互換性 (compatibility). The exact historical derivation is uncertain, but the term is a modern technical coinage.