3M
Quarter
Self explanatory.
6M
Half-year
Self explanatory.
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
Self explanatory.
DC
Ten days period
Period of 10 days.
DW
Work day
Self explanatory.
F
Period of two weeks
Self-explanatory.
H
Hour
Self explanatory.
HM
Half month
Self explanatory.
M
Month
Self explanatory.
MN
Minute
Self explanatory.
P
Four month period
Self explanatory.
S
Second
Self explanatory.
SD
Surface day
Description to be provided.
SI
Indefinite
An indefinite period.
W
Week
Period of seven days.
WD
Working days
Days when the partner company normally works.
WW
5 day work week
Monday through Friday.
Y
Year
Self explanatory.
ZZZ
Mutually defined
Period as per agreement.