WordNet sense 1 (very similar):

twin

WordNet sense 2 (similar especially in position or purpose):

corresponding

WordNet sense 3 (similar or equivalent in some respects though otherwise dissimilar):

analogous

WordNet sense 4 (similar or related in quality or character):

akin, kindred, related

WordNet sense 5 (capable of replacing or changing places with something else; permitting mutual substitution without loss of function or suitability):

exchangeable, interchangeable, standardised, standardized

WordNet sense 6 (capable of being replaced):

replaceable

WordNet sense 7 (having the same or similar characteristics):

alike, like