O/A =on or about O/B =on board OBLD=obliged OBS =observe OBT =obtain OC =our cable OC5 =our cable dated 5th OCC =occupied O.C.P,OCP=overland common point OCT =October ODR =order OFC =office OFCL=official OFF =office OFA,OFR（S）=offer（s） OK =all right or agreed OL =our letter OPEC=Organization of the Petroleum =Exporting countries OPN =open OPND=opened OPNG=opening OPT =option ORD =ordinary ORIG,ORGNL=original OT =our telex,our telegram OTLX=our telex OTHWS=otherwise OURSLVS=ourselves OZ =ounce OZWS=otherwise