| noun | something additional of the same kind “he always carried extras in case of an emergency” |
| noun | a copy that corresponds to an original exactly “he made a duplicate for the files” |
| verb | make or do or perform again “He could never replicate his brilliant performance of the magic trick” |
| verb | duplicate or match “The polished surface twinned his face and chest in reverse” |
| verb | make a duplicate or duplicates of “Could you please duplicate this letter for me?” |
| verb | increase twofold “The population doubled within 50 years” |
| adjective | identically copied from an original “a duplicate key” |
| adjective | being two identical |
| duplicate | verb | make a duplicate or duplicates of |
| double | noun | a quantity that is twice as great as another |
| repetitive | adjective | repetitive and persistent |
| repeat | noun | an event that repeats |
| repetition | noun | the act of doing or performing again |
| repeater | noun | someone who is repeatedly arrested for criminal behavior (especially for the same criminal behavior) |
| repeating | noun | the act of doing or performing again |
| replication | noun | the repetition of an experiment in order to test the validity of its conclusion |
| replica | noun | copy that is not the original; something that has been copied |
| twin | noun | a duplicate copy |
| duplicate | noun | a copy that corresponds to an original exactly |
| duplication | noun | a copy that corresponds to an original exactly |
| duplicator | noun | apparatus that makes copies of typed, written or drawn material |
| doubling | noun | increase by a factor of two |