I will try to help until I get tired of typing. Someone else will fill in where I miss.
A few of the diffent types and abbreviations:
Outside the Waistband (OWB) -- a generic term for all belt type holsters that ride outside the waistband of your pants. OWBs include paddle holsters, slides, pancakes, duty holsters, etc.
Paddle holsters are held up by a leather or plastic paddle attached to the holster. The paddle goes inside your pants, up against your body and sits down on top of your belt or waistband, so the paddle is inside your pants and the holster is outside. You dont need a belt for this type of holster (although a belt ALWAYS helps) and it is easy to take on and put off without taking off your belt.
Slide or Belt Slide Holsters are small, minimalist kinds of designs that cover the trigger guard and not a lot more -- the barrel hangs out the bottom and the grip if fully exposed. Its just enough leather to hold the gun secure. These are versatile holsters because they fit particular guns without regard to barrel length.
Pancake holsters have belt slots at each end and are designed to pull the gun in close to the body for best concealment. Pancake holsters usually enclose the full length of the barrel.
Duty holsters or hip holsters are the kinds of things your normally see cops wear. They are usually larger, bulky things not designed for concealment and usually have some kind of retention device -- like a retaining strap.
Inside the Waistband (IWB) holsters are worn inside the waistband and attach to your pants or belt with a clip or attach to your belt with loops. On the traditional kinds, most of the gun is concealed inside your pants, but the grip is exposed. Therefore, you need a cover garment of some kind. Newer kinds are "tuckable" where you can tuck in a shirt around the fastening system to cover the gun, or some are actually UWB -- under the waistband types -- where you see only the clip and everything else is inside the pants under the waistband.
There are also a number of other kinds of deep concealment holsters like shoulder holsters, pocket holsters, ankle holsters, belly band holsters, and Smart Carry/Thunderwear (worn in front inside the waistband with a support strap that does not connect to you pants in any way).
Whew. What was the question again?
Duane
www.kdholsters.com