3M
Quarter
A subdivision of a year into four equal parts.
6M
Half-year
A subdivision of a year into two equal parts.
AA
Air hour
Flight duration irrespective of time zones.
AD
Air day
Flight duration irrespective of time zones.
CD
Calendar day (includes weekends and holidays)
Period given as a number of days including weekends and holidays.
CW
Calendar week (7day)
Period given as a number of 7day-weeks including holidays.
D
Day
The twenty-four hour period during which the earth completes one rotation on its axis.
DC
Ten days period
Period of 10 days.
F
Period of two weeks
A period of time lasting fourteen days. Synonym: Fortnight.
H
Hour
One of the twenty-four sub-divisions of a day.
HM
Half month
A subdivision of a month into two equal parts.
M
Month
One of twelve divisions of the year as determined by the Gregorian calendar.
MN
Minute
A unit of time equal to 1/60 of an hour, or 60 seconds.
P
Four month period
A period of time, measured in monthly increments, consisting of four sequential months.
S
Second
A unit of time equal to 1/60 of a minute.
SD
Surface day
The voyage duration irrespective of time zones.
SI
Indefinite
An indefinite period.
W
Week
Period of seven days.
WD
Workday
Day on which work is usually done.
WW
5 day work week
Monday through Friday.
Y
Year
The period of time as measured by the Gregorian calendar in which the earth completes a single revolution around the sun.
ZZZ
Mutually defined
Period as per agreement.