Related Clues:

• Letter signoff, for short
• Vintage nos.
• 1000 and 2000 e.g.
• Eon units: Abbr.
• Sch. terms
• Era divs.
• '01 and '06, e.g.
• Decade divisions: abbr.
• Decade parts (Abbr.)
• Tree-ring meas.
• Century fractions (Abbr.)
• They may be B.C. or A.D.
• '08 and '12
• Soph and jr.
• Age-old abbr.?