Related Clues:
- Time it takes for paint to dry, seemingly
- Very long periods (US)
- Far too many years to count
- Spans of many centuries
- Not quite eternity
- Big chunk of time
- School missing first of teachers for long time
- 1 billion years, in astronomy
- Long time stretch
- Waiting time at the DMV, seemingly
- Innumerable years
- Long series of periods
- Mind-boggling spans
- Mega-years
- Earth science measures