Question:
I am getting my feet wet here, and have come across a lot of abbreviations I am unfamiliar with. If anyone could enlighten me as to what these terms mean, I would appreciate it.
OTR - Over the Road?
Vans - what does this refer to?
Reefer - What are these... some kind of trailer?
Double Drop RGN?
TA, or T/A?
HHMG?
DAC?
THanks in advance for any help. Knowing what these mean would make it easier to understand what I am reading.

Answer:
OTR - Over the Road? - Correct
Vans - The most common trailer seen on the road. Appears to be a large rectangular box with doors at the rear.
Reefer - Similar to vans except insulated and equipped with a refrigeration unit, hence the name "reefer".
Double Drop - The 'double drop" refers to an open trailer with a platform in the middle. There is a 'drop' from the front of the trailer looking backwards and a 'drop' from the rear of the trailer looking forward. A trailer with a single 'drop' from the front looking back is known as a "step deck".
RGN - stands for Removable GooseNeck. The 'gooseneck' is the front part of the trailer that attaches to the fifth wheel of the truck. This type of trailer is often used to transport heavy equipment which can be driven on/off the middle platform with the 'gooseneck' removed.
TA, or T/A - a truck stop - Travel Centers of America
HHMG - House Hold Movers Guide - a method of computing mileage from location to location
DAC - now known as DAC/USIS, an agency which maintains employment records of truck drivers.

Answer:
Thanks! I am trying to be patient with the Q's... I am busy reading a variety of threads, trying to learn as much as possible before asking too many questions. I know already tho that I will soon be asking for some updated personal opinions on the bigger trucking companies... this in preperation for getting started in the biz.

Answer:
I was talking to a friend of mine who works in the 'Roadservice / Breakdown' department the other day, and I thought I'd pass this along...
Tires on the drive and the trailer axles are known by a certain designation - not by a set of numbers like you may have learned in school, but by a three letter combination.
The driver's side of a unit is the Left side, opposite side is the Right. Tandem axles are either the Front axle or the Rear. The tires are always the Outside tire (the one seen when you look at the set), or the Inside (the one behind the outside).
When you call for service because you've a flat tire, you'll be asked which tire needs repair. You don't say "#14" because they won't have a clue which tire you are referring to. Tell the you have a flat on a trailer tire, and when they ask which tire, you say "LFI" (Left, Front, Inside) or whatever position is appropriate for the tire.
Always in that sequence - Left or Right side, Front or Rear axle, Inside or Outside tire. Instead of giving some long story about "...it's the opposite side of the driver, on the trailer, the furthest tire back, the one that's visible when you look at the tires", you simply say "I had a blowout on the trailer, the RRO tire".
There is a more complex way to describe 'B-train' tires and trailers with drag axles - we'll skip that, and stick to the simple 18-wheelers that most of us pull. "Climb back in the cab, cross your fingers for luck.
We gotta keep movin' if we're going to make a buck. "
- Roll On Down the Highway, Bachman Turner Overdrive


Answer:
I keep seeing the term "Dweller". Does this refer to a person who lives in the truck for weeks at a time? And is it just me, or does it seem to be used in a rather negative way to describe people?
When I see someone talk about "fingerprinting a load", does that mean the driver is responsible for inventorying it and taking responsibility for it?
Man, there are a LOT of threads to read!

Answer:

Nothing negative about it when used in the proper context. I, for example, am a Super Dweller; I stay on the road for months at a time.
On the other hand, if one is described as a Happy Dweller, it is akin to saying that one is a few fries short of a Happy Meal.

Hardly. It means that the driver is responsible for unloading it, one piece at a time (as opposed to using a pallet jack). He/she/it will have his/her/it's fingerprints on every piece of material in/on the trailer.

Answer:

Just make sure you know this abbreviation: B.S.
Because that is what you'll encounter the most of in trucking.
Answer:

And they likely won't get paid what that job is worth. Which makes them idiots for doing it.