| A | B |
|---|
| baker's dozen | thirteen |
| bicentennial | 200th anniversary |
| brace | two of a kind |
| centenarian | one who is 100 or older |
| centennial | 100th anniversary |
| decade | period of ten years |
| decathlon | track-and-field contest consisting of ten events |
| decimate | destroy ten percent or more or a large portion of |
| dichotomy | split |
| fathom | measure of water depth equalling six feet |
| fortnight | period of fourteen days |
| millennium | 1000 years |
| 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 | occurring or being done every four years |
| quadruped | four-footed animal |
| score | twenty |
| septuagenarian | person in his or her seventies |
| sesquicentennial | 150th anniversary |
| sexagenarian | person in his or her sixties |
| tercentennial | 300th anniversary |
| tithe | one-tenth |
| treble | triple |
| triumvirate | ruling body of three |
