| A | B |
|---|
| AD | anno domini |
| BC | before Christ |
| bicentennial | anniversary that celebrates an event that took place 200 years ago |
| centennial | anniversary that celebrates an event that took place 100 years ago |
| century | 100 years |
| chronology | order in which series of events occured |
| decade | 10 years |
| historian | one who researches and writes about the past |
| hypothesis | a preliminary answer given to a research question |
| primary source | a firsthand or original account of an historical event |
| secondary source | an account of a historical event by someone who did not witness it |
| time line | a chart that shows the chronology of historical events |
