Duplicate

Part of speech: noun (n.)

1. That which exactly resembles or corresponds to something else; another, correspondent to the first; hence, a copy; a transcript; a counterpart. I send a duplicate both of it and my last dispatch. Sir W. Temple.

2. An original instrument repeated; a document which is the same as another in all essential particulars, and differing from a mere copy in having all the validity of an original. Burrill.

Part of speech: verb (v.)

1. To double; to fold; to render double.

2. To make a duplicate of (something); to make a copy or transcript of. Glanvill.

3. To divide into two by natural growth or spontaneous action; as, infusoria duplicate themselves.

Part of speech: adjective (a.)

Double; twofold. Duplicate proportion or ratio (Math.), the proportion or ratio of squares. Thus, in geometrical proportion, the first term to the third is said to be in a duplicate ratio of the first to the second, or as its square is to the square of the second. Thus, in 2, 4, 8, 16, the ratio of 2 to 8 is a duplicate of that of 2 to 4, or as the square of 2 is to the square of 4.