Common USPS® Abbreviations
Many of the abbreviations which follow are rarely found freestanding but are used in connected series such as ChMemCom, ChAGDiv, NCom, P/V/C, etc. With the exception of ranks and grades, these abbreviations should be used with restraint and be restricted to internal correspondence and documents where the context makes there meaning clear to every potential reader. Common abbreviations found in most dictionaries may be used as needed, as may those used regularly in print. Ranks of members of the uniformed services should be expressed as used by the respective service. Spontaneously coined abbreviations and acronyms should be clearly defined in the text. Use of the slash in most USPS abbreviations is unnecessary. They are regularly used in ranks and may be inserted in other combinations to clarify their meaning. (For example, ChNomCom should become CH/NOM/COM when lower case is not preferred.)
AdAdministrative, Administration
AGAdvanced Grades
AOAdministrative Officer
APAdvanced Pilot(ing)
AsstAssistant
BBoating
BBSOn-line computer bulletin board
BudBudget
BusBusiness
/CCommander (as in V/C, Lt/C)
CaptCaptain
C/CChief Commander
CdrCommander (when used alone)
ChChairman
ClClass
Co-opCooperative (Charting)
CoChCooperative Charting
ComCommittee, Committee on, Committee for
CompSysComputer Systems
CPSCanadian Power and Sail Squadrons
CrsCourse
CSComputer Systems
DDistrict
D/CDistrict Commander
DeptDepartment
DivDivision
DLDistrict Liaison
EEducational (as in SEO)
ECElective Course(s)
EdEducation, Educational
Ed FundEducational Fund
EDEducational Development
EDMEducational Department Manual
EDNEducational Department Notice
EMEngine Maintenance
EOEducational Operations
ExExecutive (as in ExCom)
FEFlag and Etiquette
FinFinance
F/LtFlag Lieutenant
FMForms Management
GBGoverning Board (also G/B)
GMGeneral Member (of the Governing Board)
IAInstructional Aids (obsolete)
IISInformation Interchange System
IMInstructor Manual
ITInstructor Training (obsolete)
ITInformation Technology
IQInstructor Qualification
JNJunior Navigator, Junior Navigation
LBLocal Board for
LDLeadership Development
LegLegislative
LtLieutenant
MEMarine Electronics; Member Emeritus (of the GB)
MemMembership
MktgMarketing
MMMerit marks
MtgMeeting
NNavigator, Navigation, National
NFormerly designated holder of Educational Achievement Award ( written as an N underlined; spoken as Senior Navigator).  Although this is being replaced by the abbreviation "SN", it is still an acceptable alternative.
NLNational Liaison
NMNational Meetings
NomNominating, Nominations
NSBWNational Safe Boating Week
0Officer
OCOperating Committee (also OCom)
OMOperations Manual
OpOperations
OTOperations Training
PPilot(ing)
P/Past (as in P/C)
PlanPlanning
ProgProgram, Programming
PRPublic Relations
RRules
R/Rear (as in R/C)
RTRadio Technical
SSeaman; Seamanship; Squadron (as in SEO but never SC); Safety
SaSail
SecSecretary (also Secy)
SLSquadron Liaison
SMStudent Manual
SNSenior Navigator (replacing the Full Certificate or N designation); An SN has passed all elective and advanced grade classes.
SPSupplemental Program
Stf/Staff(as in Stf/C)
SuSupport
TATeaching Aids
TreasTreasurer
V/Vice (as in V/C)
WWeather
WxWeather (has replaced W to indicate Weather course)
XOExecutive Officer (also ExO)
1/LtFirst Lieutenant (also 1st/Lt)

EXAMPLES: CoChCom, DSec, P/C/C, TACom, SEO, D/1/Lt, DSO, GM/GB, ChMemCom