Framebuilders - What do these terms mean?

I've recently gotten into biking more seriously, and with that I've realized that I don't know what the hell certain words or terms mean.
For example, when I read about a frame, I see words like butted, double-butted, offset horizontal drop out, forgedeleived
and so on.
Please help me out, and post what these mean and any other things that have to do with frames.

Welcome! When I was new to cycling I just cruised around the internet and slowly learned the meaning of all the terms.
Butting generally refers to the way variable wall thicknesses are made into a frame to to achieve lower weight while maintaining strength. Double butting refers two having to different wall thicknesses, usually thicker at the ends than in the center.
Horizontal dropouts have a slot for the axle that is horizontal and often long enough to allow ease of chain tensioning.
It consists of uniform heating of a structure to a suitable temperature below the transformation range, holding at this temperature for a predetermined period of time, followed by uniform cooling.


From http://www.ayzar.com/english/estabilizado.html :

Forge relieving is applied to relieve stresses that remain locked in a structure as a consequence of a manufacturing sequence, welding, cutting, smelting, initial mechanized or forge.
This treatment supplies to pieces a great dimensional stability previously to the application of:


other heat treatments
mechanized
assemblies

The control system of these equipments enable us to process the pieces at any range of temperature.

Lots of framebuilders bits are named (http://www.framebuilding.com/)here.
There is a good bike glossary here (http://www.sheldonbrown.com/glossary.html)

Thanks a lot, both of you. The internet glossaries helped a ton.