| Answer | Crossword Clue |
|---|---|
| EON | One billion years, in astronomy |
| EON | A billion years, in astronomy |
| AEON | A billion years, in astronomy (Var.) |
| parsecs | A unit of distance used in astronomy, equal to about 3.25 light years (3.08 Î 1016 meters). One parsec corresponds to the distance at which the mean radius of the earth's orbit subtends an angle of one second of arc |
| EON | One billion years in ONE? |
| EON | One billion years, in geology |
| EON | One billion years, in geologic time |
