two copies
- duplicateExact replica of original
- carbon copyIdentical reproduction of something
- replicaFaithful scaled reproduction
- cloneGenetically identical organism
- pairTwo matching things
double · twin · xerox · photocopy · backup · mirror · ditto · reproduction · matching · identical · redundant · spare · second · both · duo · reprint · facsimile · tracing
singularity vs. multiplicity
two copiesone-of-a-kind
Having no equivalent
the only one · singular · unique · prototype