This article is from the Holocaust FAQ, by Ken McVay email@example.com with numerous contributions by others.
Einsatzgruppen: Battalion-sized, mobile, armed units of police,
primarily Security Police and SD officials, which were used
to attack and execute perceived enemies in conquered territories.
Einsatzkommando: Company-sized component of the Einsatzgruppen
Gauleiter: Supreme territorial or regional party authority(-ies)
(The term is both singular and plural). The Nazi Party divided
Germany and some annexed territories into geographical units
called Gaue, headed by a Gauleiter. (Breitman, 311)
General Government: The Nazi-ruled state in central and eastern
Poland. Headed by Governor Hans Frank. (Breitman, 311)
Final Solution: Euphemism for the extermination of European Jewry
Judenrat: Jewish community authority, appointed by the Nazis for
ghetto and village administration.
Trawniki: Labor camp, established in the Fall of 1941, in Trawniki,
S.E. of Lublin, Poland. Trawniki was part of a network of labor
camps and death camps controlled by Globocnik. Trawniki was
destroyed when Himmler ordered the death camps closed, and the
ground plowed and converted to farm use. See Encyclopedia, Vol.
IV, pp 1480-1481.
SD (Sicherheitsdienst): The SS Security Service
Sonderkommandos: Division of Einsatzgruppen, generally smaller than
Einsatzkommando, but also a more general term for special
commando units assigned particular functions. (Breitman, 311)
Military rank - here's a list from Breitman (314) which shows SS
ranks and the Western military equivalent:
Oberstgruppenfuehrer General Obergruppenfuehrer Lt. General Gruppenfuehrer Major General Brigadefuehrer Brigadier General Oberfuehrer between Brigadier & Colonel Standartenfuehrer Colonel Obersturmbannfuehrer Lt. Colonel Sturmbannfuehrer Major Hauptsturmfuehrer Captain Obersturmfuehrer 1st. Lieutenant Unterscharfuehrer Corporal Rottenfuehrer Private, First Class Sturmann Private SS-Mann no equivalent