
ABG - Acoustic Bass Guitar
B - Blend (see Post Script 1)
CIJ - Crafted in Japan
CV - Classic Vibe
EBMM - Ernie Ball MusicMan
ERB - extended range bass (i.e. more than 4 strings)
EUB - electric upright bass
FMT - Flame Maple Top
FS - For Sale
FSO - For Sale Only
FSR - Factory (Fender?) Special Run
FT - For Trade
FTO - For Trade Only
GAS - Gear Acquisition Syndrome
GLWTS - Good luck with the sale
IMHO = in my humble opinion
IMO = see above, remove humble..
J - Jazz Bass (Fender or similar)
JV - Jazz 5-string (Fender or Similar) (Or early Squier model (Joint Venture))
MIA - Made In America
MIC - Made in China
MII - Made in Indonesia
MIJ - Made in Japan
MIK - Made in Korea
MIM - Made in Mexico
MM - MusicMan
NAD - New Amp Day
NBD - New Bass Day
NCD - New Cab Day
NOS - New Old Stock
OBO - Or Best Offer (I think)
P - Precision Bass (Fender or similar)
POS = piece of shat
PUP - A shortened way of writing "pick up" of an electric guitar
PV - Peavey
QMT - Quilted Maple Top
SBMM - Sterling By MusicMan (a brand, made in Asia, not to be confused with the Sterling bass, made by MusicMan in the U.S.)
SR, SR5 - StingRay (5)
T - Tone (see Post Script 1)
V - Volume (see Post Script 1)
VM - Vintage Modified
YMMV = your mileage may vary (in my opinion)
Post Script
1) V, B, T - volume, blend and tone (e.g. VVT = a bass with two volume controls and one tone control)