When?

Adar
the sixth month of the civil year; the twelfth month of the ecclesiastic year in the Jewish calendar (in February and March)
 
work day
a day on which work is done
 
social season
the season for major social events
 
school day
the period of instruction in a school; the time period when school is in session
 
phase of the moon
a time when the Moon presents a particular recurring appearance
 
All Saints' Day
a Christian feast day honoring all the saints; first observed in 835
 
rag week
a week at British universities during which side-shows and processions of floats are organized to raise money for charities
 
years
a late time of life
 
academic term
the time during which a school holds classes
 
date
the particular day, month, or year (usually according to the Gregorian calendar) that an event occurred
 
Fast of Tevet
(Judaism) a minor fast day on Tevet 10 commemorates the beginning of the siege of Jerusalem and has also been proclaimed a memorial day for the six million Jews who died in the Holocaust
 
Messidor
tenth month of the Revolutionary calendar (June and July); the month of harvest
 
teens
the time of life between the ages of 12 and 20
 
Phalguna
the twelfth month of the Hindu calendar
 
Vendemiaire
first month of the Revolutionary calendar (September and October); the month of the grape harvest
 
Allhallows Eve
the evening before All Saints' Day; often devoted to pranks played by young people
 
extra time
playing time beyond regulation, to break a tie
 
Quinquagesima Sunday
the Sunday before Ash Wednesday (the beginning of Lent)
 
presidency
the tenure of a president
 
incubation
(pathology) the phase in the development of an infection between the time a pathogen enters the body and the time the first symptoms appear
 
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