counterpart

n. duplicate, equivalent, complement; partner, colleague

Counterparts can refer to:Counterparts (album), an album by Rush"Counterparts", a short story from Dubliners by James JoyceCounterparts, novel written by the American writer and filmmaker Gonzalo LiraCounterparts, a jazz & pop a balls group at the University of Pennsylvania websiteCounterpart theory a philosophical theory based on identity as a contingent relation. In law, a contract where the different parties' signatures appear on separate copies is said to have been signed in "counterparts".
See more at Wikipedia.org...

Noun
1. a person or thing having the same function or characteristics as another
(synonym) opposite number, vis-a-vis
(hypernym) equivalent
(hyponym) match
2. a duplicate copy
(synonym) similitude, twin
(hypernym) duplicate, duplication

n. counterpart, duplicate, equivalent, complement; partner, colleague

(n.)
One of two corresponding copies of an instrument; a duplicate.
  

(n.)
A thing may be applied to another thing so as to fit perfectly, as a seal to its impression; hence, a thing which is adapted to another thing, or which supplements it; that which serves to complete or complement anything; hence, a person or thing having qualities lacking in another; an opposite.
  

(n.)
A person who closely resembles another.
  

(n.)
A part corresponding to another part; anything which answers, or corresponds, to another; a copy; a duplicate; a facsimile.