Here is a list of most commonly used abbreviations and what they tend to stand for.
Abbreviation
Full Name + Notes (in Brackets)
2LP
Double Long Playing (33rpm, vinyl)
3LP/4LP
Triple/Quadrouple LP
45rpm/45gg
45 RPM Record (Also known as 7 Inch Single)
AC/Acetate
Acetate is The first item pressed to test the quality
BL
Blistering (vinyl has bubbled)
BOOT
Bootleg half abbreviation, half slang a bootleg is usually unreleased or live material. A illegal copy of an existing record is called a Pirated copy.
CASS SINGLE
Cassette Single
CC
Cut Corner (a Cut Out or promo item)
CD3
3" Compact Disc Single
CD5
5" Compact Disc Single
CO
Company (Usually refers to sleeve)
CUT
Cut Out (type of cut out not specified) Used since the 80's for promo items and deletions
DC
Discoloration (on label or sleeve)
DCC
Digital Compact Cassette
DEL
Deleted ( This means that the record label will not manufacture this release until further notice)
DHL
Drill hole Through Label
DJ
Disc Jockey (Usually in reference to a promo copy for DJ's)
EW
Edge Warp (rarely used)
EX
Excellent, refers to the condition of record
F
Fair, refers to the condition of record
G
Good, refers to the condition of record
HCRW
Heavy Cover Ring Wear
LPR
Later Pressing (Not original)
M
Mint (perfect), Refers to the condition of record
M/C
Music Cassette (tape)
NM
Near Mint, Refers to the condition of record
NOC
No Original Centre (mainly old European 45s with push out middles)
OBI
Original Band Intact (refers to paper band on Japanese LPs)
OOP
Out of print (Release is not yet deleted, but the record company is currently not manufacturing it)
Orig, ORG
Original (pressing)
P
Poor, Refers to the of record (Rarely Used)
P/C, PC
Picture Cover (pretty much the same as picture sleeve!)
PD, PDK, PIC DISC
Picture Disc
PROG
Progressive (Music Style of '70)
PROMO, PRO, PR
Promotional Copy
RPM
Revolutions per minute
RS / GS
Rubber stamped / Gold stamped
SC
Saw Cut (a form of cut out)
SCR
Scratch (the record is scratched)
PIRATE
Illegal copies of officially released recordings
SOFC
Sticker on Front Cover
SS
Seam split (usually happens when distributor or manufacturer ships item
STKRD, STKRED, STK
Stickered
TOIC
Tear on Inside cover
TS
Tape Seam (Repaired with cellotape)
UNP
Unplayed, Refers to the condition of record
VG
Very Good, Refers to the condition of record
WOFC
Writing on front cover
WOIC
Writing on Inside cover