Key terms that will help your understanding of this topic:

Soviet Union
Breakaway province (you may need to read through some articles to understand what it clear definition found Online)
De facto
Autonomous Region
South Ossetian Autonomous Oblast
Georgian Soviet Socialist Republic (GSSR)
Sochi Agreement
Joint Control Commission (JCC)
Mikheil Saakashvili
Rose Revolution
Eduard Shevardnadze
North Atlantic Treaty Organization (NATO)
Caucasus Region
2006 South Ossetian Independence Referendum
Vladimir Putin
Dmitry Medvedev
Georgia Train & Equip Programme / Georgia Sustainment & Stability Operations Programme (how was the U.S. involved?)
Immediate Response 2008
Caucasus Frontier
Operation Clear Field
Cluster Bombs
Roki Tunnel
Joint Peacekeeping Forces Group (JPKF)
United Nations (UN)
Battle of Tskhinvali
Six-Point Peace Plan
2008 Beijing Olympics
Nicolas Sarkozy
Sergei Bagapsh