(idiomatic) To make someone happy, or be a source of satisfaction, for the rest of the day.

(idiomatic) A nonchalant dismissal of a significant accomplishment.

(US Army, US Air Force and US Navy, derogatory, slang) Newly-commissioned graduate of three-month Officer Candidate School (Army, Air Force), Midshipman School (Navy), or Direct Commissioning program.

Alternative form of St. Stephen's Day.

(Christianity) A Christian holiday commemorating Saint Stephen the protomartyr (first Christian martyr; died 34 C.E.), falling immediately after Christmas Day (on December 26 in the Western Church and on December 27 in the Eastern Orthodox Church).

plural of red-letter day

alternative form of red letter day

A typical bad day.

(idiomatic) A new beginning; a fresh start; an important, promising turning point.

(finance) A convention on how interest accrues over time for a variety of investments, including bonds, notes, loans, medium-term notes, swaps, and FRAs. It determines the number of days between two coupon payments.