You found your ancestor’s obituary. Yay! There’s just one problem. It says that he died “on the 5th inst.” Or what about that marriage announcement you found? The happy couple got married “on the 27th ult.” They sort of look like dates, but what are “inst” and “ult”?

Ult. and inst. are abbreviations that refer to months, but in a relative way. Let’s take a look.

Inst. = Instant = Current Month

Inst. is an abbreviation for instant, which refers to the “present or current month,” according to Merriam-Webster.

G.W. Spurgeon died “on the 3rd inst.” That alone doesn’t give us enough information to know which month it refers to. We need to know when this obituary was published.

The obituary appeared in the Kansas Farmer on 17 December 1879. Since “inst.” refers to the present or current month, Spurgeon died 3 December 1879.

Ult. = Ultimo = Previous Month

Ult. is short for ultimo, meaning “of or occurring in the month preceding the present.” Like inst., we can’t know which month it’s referring to unless we know what the “present” month is.

Ult. can trip us up. When we read that Pvt. Guy De St. Croix died “5th ult.” and the article is datelined 7 August, it’s easy to think he died 5 August. He actually died 5 July. Ult. refers to the month preceding the present. The article is in August, so the month preceding would be July. (If he had died in August, he would have died “5th inst.”)