Normal AC coach : Usually refers to the self-generating AC coaches manufactured by Integral coach factory (ICF). These coaches generate electricity while the train is moving and that is used to power the AC, lights fans etc. These are the blue color coaches normally seen all across IR.
LHB AC : These are the latest set of coaches, being used in the Rajdhani, Shatabdhi and some other SF trains. These coaches do not have any facility for electricity generation and depend on other sources. either HOG or EOG for powering AC, lights and fans etc.
EOG...
more... : End on generation (EOG) coaches contain diesel generators. These can be used to power the rake. Usually this is what you see in all LHB coach trains currently.
HOG : Head on Generation (HOG). In this system, the electricity required for the rake is supplied directly by the loco. In case of an electric locomotive, it takes the power from the over head wires and supplies it to the rake. In case of a diesel loco, usually an extra diesel generator is provided in the locomotive just for supplying electricity to the rake.