When?

triennial
the 300th anniversary (or the celebration of it)
 
Saint Joseph
a Christian holy day
 
Trinity Sunday
eighth Sunday after Easter
 
diamond jubilee
an anniversary celebrating the passage of 60 years
 
eve
the latter part of the day (the period of decreasing daylight from late afternoon until nightfall)
 
United Nations Day
a day for celebrating the founding of the United Nations
 
life
the period between birth and the present time
 
Victory Day
the day of a victory
 
Saint Valentine's Day
a day for the exchange of tokens of affection
 
Enlightenment
a movement in Europe from about 1650 until 1800 that advocated the use of reason and individualism instead of tradition and established doctrine
 
quarter-century
a period of 25 years
 
half-term
a short vacation about halfway through a school term
 
Middle Ages
the period of history between classical antiquity and the Italian Renaissance
 
Reconstruction Period
the period after the American Civil War when the southern states were reorganized and reintegrated into the Union; 1865-1877
 
summer school
an academic session during the summer; usually for remedial or supplementary study
 
haying
the season for cutting and drying and storing grass as fodder
 
centenary
the 100th anniversary (or the celebration of it)
 
rainy day
a (future) time of financial need
 
outing
a day devoted to an outdoor social gathering
 
Bastille Day
a legal holiday in France celebrating the storming of the Paris bastille in 1789
 
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