Historical clue formulations

• — — 2024-03-28
• Symbol for a break — 2017-09-17
• Punctuation mark akin to a semicolon — 2016-09-12
• Linear punctuation mark — 2015-08-05
• Part of a suspended sentence? — 2015-02-07
• Frequent feature of Emily Dickinson poetry — 2006-07-21
• Punctuation used for stress — 2006-01-24
• Ellipsis alternative — 2004-02-17
• Colon substitute — 2003-05-11
• Clause separator — 1999-12-02
• _ — 1998-07-19