interchangeable

Etymology

From interchange + -able.

adj

1. Freely substitutable; that may be swapped at will.
   Eli Whitney's development of interchangeable parts was a breakthrough for modern manufacturing. Prior to that, each part had to be made custom.
   Sometimes the same words mean opposite things. Sometimes the opposite is true. Shock absorbers are called shocks. Slow down and slow up are interchangeable. 1997, George Carlin, Brain Droppings, New York: Hyperion Books, →LCCN, →OCLC, →OL, page 104
   The English, until relatively recently, seem to have imagined “English” and “British” to be interchangeable, as if Britain was just a bigger England. 16 September 2014, Ian Jack, “Is this the end of Britishness”, in The Guardian
2. Following each other in alternate succession; alternating.

noun

1. Anything that can be interchanged; a substitute.