APFT - Army Physical Fitness Test
cMVO2 - Cadence maximum VO2
DD - Dragon Door
Density - Getting more work done in less time. This usually translated to more weight being lifted per unit time, such as more pounds or kilograms per minute.
EDT - Escalating Density Training
ETK - Enter the Kettlebell, 2006 book/DVD update on Kettlebell training from Pavel
GTG - Grease the Groove, or Greasing the Groove. See Question #1 on the fourth post
GS Training - Girevoy Sport Training
GVT - German Volume Training
HIIT - High Intensity Interval Training
HKC - Hardstyle Kettlebell Certification, made in the year 2009, a 1 day certification vs. 3 day RKC certification
HS Training - Hard Style Training (the pre-dominant style on this forum)
HTT - High Tension Techniques
Intensity - The amount of weight lifted per repetition or speed per repetition of an exercise.
Max VO2, or VO2 Max - VO2 max - Wikipedia, the free encyclopedia
MetCon - Metabolic Conditioning
MP - Military Press
NW - Naked Warrior, Bodyweight Strength Training Book/DVD by Pavel
OAP/OAPU - One Arm Pullup/One Arm Push Up
PM - Program Minimum, the prerequisite training regimen to the RoP described in ETK
PR/PB - Personal Record/Personal Best
PTP - Power to the People, a book/DVD on barbell training
RIS - Relax into Stretch
RKC - Russian Kettlebell Challenge, 2001 book/DVD, the first book that started it all
RKC (more common) - Also stands for Russian Kettlebell Certification, a 3 day certification by Dragon Door.
RoP (usually abbreviated in this form, also seen as ROP) - Rite of Passage, a training regimen described in ETK
RoTK/RTK - Return of the Kettlebell, a book/DVD with an emphasis on double Kettlebell work.
TGU - Turkish Get Up, outstanding full body exercise
Volume - The amount of weight lifted in a session, or a day, or a week. Usually monitored to enhance performance and avoid over training.
VWC - Viking Warrior Conditioning, phenomenal book by Kenneth Jay, Master RKC on Max VO2 training
WTH Effect - "What the hell?" effect. Using Kettlebells tends to have a very good transfer to other exercises, and many users tend to see other lifts go up, even though they are not specifically training those lifts