| A | B |
|---|
| baker's dozen | thirteen |
| bicentennial | 200th anniversary |
| brace | two of a kind; pair; couple |
| centenarian | one is who is 100 or older |
| centennial | 100th anniversary |
| decade | period of ten years |
| decathalon | track and field contest consisting of ten events |
| decimate | destroy ten person or more or a large portion of |
| dichotomy | division in two;split |
| fathom | measure of water depth equaling six feet |
| fortnight | period of 14 days, two weeks |
| millennium | 1000 years, 1000th anniversary |
| nonagenarian | person in his or her nineties |
| octogenarian | person in his or her eighties |
| pentagon | plane figure of five sides and five angles |
| plurality | victor's margin over the runner-up when no candidate has a majority of the votes |
| quadrennial | occuring or being done every four years |
| quadruped | four footed animal |
| score | group of twney |
| septuagenarian | person in his or her 70s |
| sesquicentennial | 150th anniversary |
| sexagenarian | person in his or her 60s |
| tercentennial | 300th anniversary |
| tithe | one-tenth; tenth part of a person's income paid as a contribution or tax to support a religious establishment |
| treble | multiply by three; triple |
| triumvirate | ruling body of three, troika |
