| Interesting historical periods |
| Astronomical time period |
| Historical meeting places |
| A notable period of history |
| Actor who supposedly "destroyed the periodic table, because he only recognizes the element of surprise |
| Astronomical time periods |
| Term for a presidential period, historically |
| Time period between birthdays |
| An extremely long period of time |
| Periodical publisher |
| Pre-event periods |
| Periods from midnight to noon: Abbr. |
| Geologic period |
| Periods in history |
| Historical chapters |
| Between-periods equipment |
| Very long period |
| Notable historical spans |
| Online periodical, briefly |
| A very long period of time |
| Accentuated periods |
| Period ending about 9000 B.C. |
| Periods of inactivity |
| Amount of land a pair of oxen could plow in a day, historically |
| Powerful ruling period |
| Phooey on that prehistorically set comic strip! |
| Before-noon periods: Abbr. |
| Enero-to-diciembre periods |
| Fan-produced periodical |
| Geology class periods [subscribe to the best indie xwords today at avxwords.com] |