Related Clues:

• Celebrates a birthday
• Huge time span
• Long division?
• Vast stretch
• Plenty of time?
• Many, many centuries
• Nearly forever
• Long geologic time division
• Yellows, or mellows
• Nearly infinite perioD
• A gazillion years, seemingly
• Seemingly endless time
• Many a doctor's office wait, seemingly
• Yellows or grays, say
• Billion-year span