(computing, idiomatic) (of vulnerability) newly discovered, and therefore still not fixed and possibly exploited by hackers or other criminals

(computing, idiomatic) vulnerability that has been discovered recently, and is yet unpatched or unmitigated; zero-day vulnerability

plural of day trip

The day on which a President and a Vice-President of the United States takes office, now on January 20 after a Presidential election, before 1936 on March 4.

(US politics) The day on which general elections are held in the United States: the Tuesday following the first Monday in November.

(US, slang) Thanksgiving Day; Turkey Day.

plural of field day

plural of sports day

A school day set aside for athletics events.

A day celebrating George Washington and other presidents, a federal holiday in the United States, celebrated on the third Monday of February (formerly on the 22nd of February).