Related Clues:

• Old, to a car buff
• Wine bottle number
• Almanac span
• YTD part
• It starts with a celebration
• Certain cycle
• Revolution duration
• 1984, e.g.
• Junior or senior, e.g.
• Part of Y2K
• Orbital period
• Revolutionary period?
• Revolution time
• Whisky or wine datum
• 669 Martian days