Historical clue formulations

• Abbr. in a formal salutation — 2019-11-16
• Gentlemen: Abbr. — 2016-04-24
• Old letter opener: Abbr. — 2014-03-28
• Gentlemen: Abbr. — 2013-12-30
• Counterpart of Mmes. — 2013-09-23
• Quaint letter-opening abbr. — 2013-08-17
• Lead-in to multiple last names — 2011-05-07
• Abbr. preceding multiple surnames — 2009-06-02
• Quaint letter opener: Abbr. — 2009-05-01
• Gentlemen: Abbr. — 2008-06-09
• Salutation abbreviation — 2007-08-03
• Old-fashioned letter opener: Abbr. — 2007-06-09
• Abbr. in a salutation — 2004-10-17
• Opposite of misses: Abbr. — 2003-02-23
• Abbr. at the head of a letter — 2002-05-26
• Abbr. before multiple surnames — 2002-03-31
• Letter abbr. — 2001-08-05
• Polite title: Abbr. — 2001-03-02
• Abbr. preceding multiple surnames — 1998-10-04
• Salutation abbr. — 1996-10-24