February

• leap day

  The name of the day that is added during a leap year.

• Groundhog Day

  If the ground hog emerges and sees his shadow on this day, there will be 6 more weeks...

• Lincoln's Birthday

  The day on which President Abraham Lincoln is remembered.

• Valentine Day

  A day for the exchange of tokens of affection.

• Washington's Birthday

  The day on which George Washington is remembered.

June

• Jefferson Davis' Birthday

  Celebrated in southern United States.

• Flag Day

  Commemorating the adoption of the United States flag in 1777.

• Father's Day

  US: third Sunday in June.

• Midsummer Eve

  The night before Midsummer Day.

Great Britain

• November 5

  Anniversary of the discovery of the Gunpowder Plot.

• rag day

  A day on which university students hold a rag.

• speech day

  An annual day in the schools when speeches are made and prizes are distributed.

April

• April Fools'

  The first day of April which is celebrated by playing practical jokes.

• Pan American Day

  A day celebrating political and economic unity among American countries.

• Patriot's Day

  The 3rd Monday in April; Massachusetts and Maine celebrate the battle of Lexington...

May

• May Day

  Observed in many countries to celebrate the coming of spring; observed in Russia and related...

• Mother's Day

  Second Sunday in May.

• Armed Forces Day

  The 3rd Saturday in May.

September

• Citizenship Day

  Celebrated in the United States.

• American Indian Day

  US: the 4th Friday in September.

January

• Inauguration Day

  The day designated for inauguration of the United States President.

• Tet

  The New Year in Vietnam; observed for three days after the first full moon after January 20...

Also contains

• anniversary

  The date on which an event occurred in some previous year (or the celebration of it...

• holiday

  A day on which work is suspended by law or custom; "no mail is delivered on federal holidays";...

• New Year's Eve

  The last day of the year.

• saint's day

  A day commemorating a saint.

• wedding day

  The day of a wedding.

• United Nations Day

  A day for celebrating the founding of the United Nations.

• Halloween

  The evening before All Saints' Day; often devoted to pranks played by young people.

• red-letter day

  A memorably happy or noteworthy day (from the custom of marking holy days in red...

• payday

  The day on which you receive pay for your work.

• polling day

  The day appointed for an election; in the United States it is the 1st Tuesday after...

• field day

  (military) a day for military exercises and display.

• field day

  A day for outdoor athletic competition.

• ides

  In the Roman calendar: the 15th of March or May or July or October or the 13th of any other...

• market day

  A fixed day for holding a public market.

• school day

  Any day on which school is in session; "go to bed early because tomorrow is a school...

• washday

  A day set aside for doing household laundry.

• Walpurgis Night

  Eve of May Day.

• Robert E Lee's Birthday

  Celebrated in southern United States.

• Admission Day

  In some states of the United States: a legal holiday commemorating the day the state...

• Cinco de Mayo

  The fifth of May which is observed in Mexico and Mexican-American communities in the...

• Arbor Day

  A day designated for planting trees.

• degree day

  The day on which university degrees are conferred.

• St Patrick's Day

  A day observed by the Irish to commemorate the patron saint of Ireland.

• V-day

  The day of a victory.

• Texas Independence Day

  Texans celebrate the anniversary of Texas' declaration of independence from...