Synonyms for Interchangeable (same or very similar meaning)
WordNet sense 1 (having similarity in size, shape, and relative position of corresponding parts):
symmetric, symmetrical
WordNet sense 2 (capable of replacing or changing places with something else; permitting mutual substitution without loss of function or suitability):
exchangeable, similar, standardised, standardized
WordNet sense 3 (capable of being replaced):
replaceable
From the ODE community, based on WordNet
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