Counterpart

n.	1.	A part corresponding to another part; anything which answers, or corresponds, to another; a copy; a duplicate; a facsimile. In same things the laws of Normandy agreed with the laws of England, so that they seem to be, as it were, copies or counterparts one of another. - Sir M. Hale.
	2.	(Law) One of two corresponding copies of an instrument; a duplicate.
	3.	A person who closely resembles another.
	4.	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. O counterpart Of our soft sex, well are you made our lords. - Dryden.

Noun	1.	counterpart - a person or thing having the same function or characteristics as another Synonyms: opposite number, vis-a-vis
	2.	counterpart - a duplicate copy Synonyms: similitude, twin

COUNTERPART, contracts. Formerly each party to an indenture executed a separate deed; that part which was executed by the grantor was called the original, and the rest the counterparts. It is now usual for all the parties to execute every part, and this makes them all originals. 2 Bl. Com. 296.
     2. In granting lots subject to a ground rent reserved to the grantor, both parties execute the deeds, of which there are two copies; although both are original, one of them is sometimes called the counterpart. Vide 12 Vin. Ab. 104; Dane's Ab. Index, h.t.; 7 Com. Dig. 443; Merl. Repert. mots Double Ecrit.

ally, alter ego, analogon, analogue, associate, brother, clone, close copy, close match, coequal, cognate, companion, compeer, complement, congenator, congener, coordinate, correlate, correlative, correspondent, ditto, double, dupe, duplicate, duplication, each other, equal, equipollent, equivalent, facsimile, fellow, image, kindred spirit, like, likeness, match, mate, model, near duplicate, obverse, one another, opposite number, parallel, peer, pendant, picture, quadruplicate, reciprocal, reciprocatist, reciprocator, repetition, replica, replication, representation, reproduction, rival, second self, similitude, simulacrum, sister, soul mate, such, suchlike, tally, the like of, the likes of, triplicate, twin, vis-a-vis