duplicate

adj

1. (not-comparable)Being the same as another; identical, often having been copied from an original.

   “This is a duplicate entry.”

2. (not-comparable)In which the hands of cards, tiles, etc. are preserved between rounds to be played again by other players.

   “duplicate whist”

   “duplicate Scrabble”

verb

1. (transitive)To make a copy of.

   “If we duplicate the information, are we really accomplishing much?”

   “Can you duplicate this kind of key?”

2. (transitive)To do repeatedly; to do again.

   “You don't need to duplicate my efforts.”

3. (transitive)To produce something equal to.

   “He found it hard to duplicate the skills of his wife.”

noun

1. (countable, uncountable)One that resembles or corresponds to another; an identical copy.

   “This is a duplicate, but a very good replica.”

   “July 20, 1678, William Temple, letter to the Lord Treasurer I send a duplicate both of it and my last dispatch.”

2. (countable, uncountable)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
3. (countable, uncountable)A pawnbroker's ticket, which must be shown when redeeming a pledged item.

   “"Sir, I hope you will excuse what I am going to say; but having observed that you frequently pledge similar goods to these at our shop, which are afterwards taken out by other persons, I take for granted you are in the habit of selling the duplicates;[…]"”

4. (uncountable)The game of duplicate bridge.

   “The momentary madness which infects bridge players occurs frequently at rubber bridge and duplicate; and though it rarely results in murder, it often terminates marriages and close friendships[…]”

5. (uncountable)The game of duplicate Scrabble.
6. (countable, uncountable)A biological specimen that was gathered alongside another specimen and represents the same species.

   “Each collection, which may be a unicate or several specimens as duplicates in several herbaria, constitutes a record in the Conifer Database.”