You might have noticed that our "Letters of the Day" frequently contain the word "inst.," which always seem to reference a date of some kind. Having confined most of my previous research to the very late 19th century/ early 20th century, this was a convention that I hadn't run across very often until I started here at NMHM. It occurred to me that some readers out there might be confused, or at least curious, as I was.
These abbreviations are common in correspondence from the Civil War era, but have (obviously) fallen out of fashion. So here goes:
"Inst." is an abbreviation for "instant", which refers to the current month or year, depending upon its context. For example, "the 17th of December, inst.," means December 17 of the current year. "The 17th, inst.," means the 17th day of the current month.
You may also see the word "ult." - an abbreviation for "ultimo" - which means the previous month or year.