Historical clue formulations

• Greek letters before chis — 2023-11-20
• Some college Greeks — 2019-10-15
• Sorority letters — 2015-03-15
• Fraternity letters — 2007-11-07
• Greek letters — 2005-05-19
• Diameter symbols, in math — 2003-02-02
• Letters from Crete — 2002-04-25
• Greek characters — 1997-08-21
• Fraternity letters — 1997-02-06
• Letters from Greece — 1996-11-03
• Key letters — 1995-11-21