1) Alternation 2) Commutability 3) Convertibility 4) Exchangeability 5) Fungibility 6) Inconvertibility 7) Interchangeableness 8) Permutability 9) Permutableness 10) Replaceability 11) Substitutability 12) Transferability 13) Transposability 
[computer science] In computer science, interchangeability is an ability that an object can be replaced by another object without affecting code using the object. That chance usually requires two objects share an interface that is either same strictly or compatible in particular case. See encapsulation article for detail. ...
• (n.) The state or quality of being interchangeable; interchangeableness.
The characteristic of a design that allows direct replacement of one item with another without requiring any modifications. 
In`ter·change`a·bil'i·ty noun The state or quality of being interchangeable; interchangeableness.