| verb | increase twofold “The population doubled within 50 years” |
| verb | hit a two-base hit |
| verb | bend over or curl up, usually with laughter or pain “He doubled and vomited violently” |
| verb | do double duty; serve two purposes or have two functions “She doubles as his wife and secretary” |
| verb | bridge: make a demand for (a card or suit) |
| verb | make or do or perform again “He could never replicate his brilliant performance of the magic trick” |
| adjective | twice as great or many “ate a double portion” |
| double | noun | a quantity that is twice as great as another |
| doubling | noun | increase by a factor of two |
| 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 |