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The Advance Wars series has used abbreviations for its units since AW 1 on the GBA. They are generally very easy to figure out and exist only to save space. In addition gamers and message board posters have been using acronyms for commonly used terms.

Abbreviation	Definition
A-Air	Anti-Air.
AoE	Area of Effect, attacks that hit all in a given area.
Artlry	Artillery.
CO	Commanding Officer. Also, CO Power meaning the first tier special ability.
dmg	Damage.
FoW	Fog of War.
HP	Hit Points or Health Points. Both have the same meaning and use.
HQ	Headquarters.
Inftry	Infantry.
JPN	Japan or Japanese, using JAP is considered offensive.
M Gun	Machine Gun.
OHKO	One Hit Knock Out, or Instant Kill.
SCO	Super Commanding Officer. Usually in the form of SCO Power, meaning the second tier special ability.
TBS	Turn Based Strategy .
Torps	Torpedoes.