As we work through the Ranger Handbook it is important to keep track of the acronyms and abbreviations used throughout. Here is a handy reference if you lose track.
1SG- First Sergeant
AO- Area of Operation
CASEVAC- Casualty Evacuation
CCIR- Commander's Critical Information Requirements
CCP- Casualty Collection Point
CP- Command Post
FO- Forward Observer
FRAGO or FRAGORD- Fragmentary Orders
HQ- Headquarters
IR- Information Requirements
KIA- Killed In Action
LP- Listening Post
METT-TC- Mission, Enemy, Terrain/Weather, Troops available, Time available, Civil considerations
NLT- No Later Than
OAKOC- Observation/Fields of Fire, Avenues of approach, Key terrain, Obstacles, Cover/Concealment
OP- Observation Post
OPORD- Operations Order
ORP- Objective Rally Point
PIR- Priority Intelligence Requirements
PL- Platoon Leader
PSG- Platoon Sergeant
RTO- Radio Telephone Operator (or sometimes just Radio Operator)
SITREP- Situation Report
SL- Squad Leader
TL- Team Leader
WARNORD- Warning Order
WIA- Wounded In Action
WSL- Weapons Squad Leader
XO- Executive Officer