up 31, thirty-one, thirty-first, or 31st in Wiktionary, the free dictionary. 31 may refer to: 31 (number) 31 BC AD 31 1931 CE ('31) 2031 CE ('31) Thirty...

31 (thirty-one) is the natural number following 30 and preceding 32. It is a prime number. 31 is the 11th prime number. It is a superprime and a self...

January 31 is the 31st day of the year in the Gregorian calendar; 334 days remain until the end of the year (335 in leap years). 314 – Pope Sylvester I...

July 31 is the 212th day of the year (213th in leap years) in the Gregorian calendar; 153 days remain until the end of the year. 30 BC – Battle of Alexandria:...

The Mikoyan MiG-31 (Russian: Микоян МиГ-31; NATO reporting name: Foxhound) is a supersonic interceptor aircraft developed for the Soviet Air Forces by...

March 31 is the 90th day of the year (91st in leap years) in the Gregorian calendar; 275 days remain until the end of the year. 307 – After divorcing his...

October 31 is the 304th day of the year (305th in leap years) in the Gregorian calendar; 61 days remain until the end of the year. 475 – Romulus Augustulus...

August 31 is the 243rd day of the year (244th in leap years) in the Gregorian calendar; 122 days remain until the end of the year. 1056 – After a sudden...

ISO 31 (Quantities and units, International Organization for Standardization, 1992) is a superseded international standard concerning physical quantities...

Ulysses 31 (Japanese: 宇宙伝説ユリシーズ31（サーティーワン）, Hepburn: Uchū Densetsu Yurishīzu Sātīwan, lit. "Space Legend Ulysses 31", French: Ulysse 31) is an anime series...