Counterpart

(-părt.) The duplicate or corresponding part of anything. Also, the part which fits another; as, the key of a cipher.- (Mus.) The part to be applied to another; thus, the ba is the counterpart to the treble. -(Law.) When the parts of an indenture are interchangeably executed by the several parties, that executed by the grantors is termed the original, and the rest are counterparts. Adeed made by one party is not indented, but polled or shaven quite even; and is, therefore, styled a deed-poll or single deed. [s. 237]