The act of salvaging or in some manner restoring a discarded item to yield something usable. The act of using again, or in another place.

Is there such a word as reusability?

The definition of reusability in the dictionary is the state or quality of being reusable.

Is reusable a noun or adjective?

able to be used again; especially after salvaging or special treatment or processing. (of a program) Able to be executed by several tasks without being reloaded; either reentrant or serially reusable.